ChromeCast fails:
Try setting the option Settings -> Playback -> Use device proxy. It is a work around for Chromecast not accepting self-signed certificates.

First level in Library are actually groups of artists:
In the option menu, deselect "First level artists". This will make it so that the entire first level of directories shown will be treated like groups of artists instead of the artists themselves. ]]> Shuffle play Go Offline Go Online Settings Album Lists Per Folder Recently added Recently played Most played Top rated Starred Random Genres Decades Alphabetically Videos @string/main.albums_genres @string/main.albums_newest Top Played @string/main.albums_recent @string/main.albums_frequent Press back again to exit Completed scan of Server Artist Title Search Shuffle Refresh Play Play Last Exit Settings Help About Add To Playlist Remove From Playlist Deleted playlist %s Failed to delete playlist %s Send Log Set Timer Check For New Episodes Add Channel Keep Synced Stop syncing Show all songs Show Artist Share Delete Cache Cast To Device FAQ Add User Rescan Server Set Rating Last.FM Top Tracks Similar Artists Missing Artists Start Radio First level artists Playlists Update Information Updated playlist information for %s Failed to update playlist information for %s Overwrite existing playlist Add to Playlist Create New Delete Playlist Search Search Click to search No matches, please try again Artists Albums Songs Please wait... Loading Artist Bio %d selected. Offline Error: No SD card available. Warning: No network available. Warning: you only have %s left Server not licensed. %d trial days left. Get unlimited downloads by donating to Subsonic. Now Later Trial period is over Offline songs waiting to be synced Process %1$d offline scrobbles? \nProcess %2$d offline stars? Use action as default Successfully synced %1$d songs Successfully synced %1$d of %2$d songs Failed to sync songs Blank %d songs %d albums This podcast had an error while downloading on the server. The server must download it first. This podcast has not been downloaded on the server. The server must download it first. This podcast channel is being initialized on the server. Please reload after a moment. Download on server Delete from server Now downloading %s on the server The server is checking for new podcasts now Deleted podcast %s Failed to delete podcast %s URL: Failed to add podcast Invalid podcast channel: %s Delete podcast Podcast Channels Playlist is empty Shuffle list is loading... Downloading - %s Waiting for WiFi or local (non-roaming) network to download Buffering Shuffle mode Artist radio Show Album Lyrics Remove all Screen on Shuffle Toggle Save playlist Playlist was shuffled Remove played songs Save playlist Enter the playlist name: Saving playlist \"%s\"... Playlist was successfully saved. Failed to save playlist, please try later. Repeat off Repeat all Repeat song Remote control is not supported. Please upgrade your Subsonic server. Remote control is not available in offline mode. Remote control is not allowed. Please enable jukebox mode in Users > Settings on your Subsonic server. Start Timer Stop in %1$s Video needs to be downloaded first No player can play this stream Playing: %1$d/%2$d Create bookmark Bookmark created Failed to create bookmark Downloading %1$d songs Current: %1$s Current: %1$s \nEstimated Size: %2$s Failed to load continue from where you left off on another device at Thumbs Up Thumbs Down Batch Mode 0.5x 1x 1.5x 2x 3x Custom New podcasts available New songs in playlists New albums available New starred songs available Starred \"%s\" Unstarred \"%s\" Failed to update \"%s\", please try later. My Playlists Shared Playlists Failed to grab list of playlists Added %1$s songs to \"%2$s\" Failed to update \"%s\", please try later. Removed %1$s songs from \"%2$s\" Delete bookmark Delete the bookmark for Deleted the bookmark for \"%s\" Failed to delete the bookmark for \"%s\" Bookmark Details Resume playing? Resume playing \'%1$s\' from %2$s Resume Start Over Rate \"%s\" Rating set for \"%s\" Failed to set rating for \"%s\" Rating removed for \"%s\" Failed to remove rating for \"%s\" Error Skipped Downloading No lyrics found Error Settings Test connection Add Server Remove Server Servers Unused Name Server address Local network SSID Current SSID: %s Local network address Username Password Open in browser Whether or not syncing is enabled for this server Sync Enabled Music cache Songs to preload (Wifi) Songs to preload (Mobile) Cache size Cache location Invalid cache location. Using default. The cache location you have set is no longer writable. If you recently upgraded your phone OS to KitKat 4.4, then the way apps write to the SD Card has changed so that they can only write to a specific location. The location that DSub uses has already been automatically changed to the correct location. In order to delete all of the old app data, you will need to mount the SD Card on your computer and delete the old folder manually Internal External Clear Cache Finished clearing cache Testing connection... Connection is OK Connection is OK. Server unlicensed. Connection failure. Please specify a valid URL. Please specify a valid username (no trailing spaces). Appearance Theme Light Dark Black Holo Day/Night Day/Black Night Fullscreen Hide as many UI elements as Android will allow Display Track # Display Track # in front of songs if one exists Sort By Year Sort albums by year, or by alphabetical Open To Tab Open directly to this tab Network Max Audio bitrate - Wi-Fi Max Audio bitrate - Mobile 32 Kbps 48 Kbps 64 Kbps 80 Kbps 96 Kbps 112 Kbps 128 Kbps 160 Kbps 192 Kbps 256 Kbps 320 Kbps Max Video bitrate - Wi-Fi Max Video bitrate - Mobile 200 Kbps 300 Kbps 400 Kbps 500 Kbps 700 Kbps 1000 Kbps 1500 Kbps 2000 Kbps 3000 Kbps 5000 Kbps Unlimited Wi-Fi streaming only Only stream media if connected to Wi-Fi Don\'t stream when roaming Don\'t stream media while roaming Network Timeout 10 seconds 15 seconds 30 seconds 45 seconds 60 seconds 0 song 1 song 2 songs 3 songs 5 songs 10 songs Unlimited Clear search history Search history cleared Other settings Scrobble to Last.fm Remember to set up your Last.fm user and password on the Subsonic server Hide from other Hide music files from other apps. Takes effect next time Android scans your phone for music. Media buttons Respond to phone, headset and Bluetooth media buttons Keep screen on Keeping the screen on while downloading improves download speed. Play Shuffle Playlist Size Sleep Timer Sleep Timer Duration Off On Always On Temporary Loss of Focus Always Pause Pause, lower volume when requested Always lower volume Do Nothing Keep played songs Remove all played songs Keep last played song Keep 2 played songs Keep 3 played songs Pause on Disconnect Pause Do Nothing Persistent Notification Show the notification even after pausing. Press the stop button to clear it away. Gapless Playback If you are seeing strange bugs during playback, turning this off may help. Chat Refresh Rate (Secs) Chat Enabled Whether or not to display the chat listing in the pull out drawer Video Video Player Raw (Requires Subsonic 4.8+) HTTP Live Stream (HLS) (Requires Subsonic 4.8+) Direct Transcode (Requires video -> mp4 or similar setup on Server) Flash (Requires Plugin) Cache/Network Playback Hide Widget Hide widget after exiting app Podcasts Enabled Whether or not to display the podcast listing in the pull out drawer Bookmarks Enabled Whether or not to display the bookmarks listing in the pull out drawer Internet Radio Enabled Whether or not to display the internet radio listing in the pull out drawer Shares Enabled Whether or not to display the shares listing in the pull out drawer Sync Sync Enabled Whether or not playlists or podcasts are periodically checked for changes Sync Interval 15 Minutes 30 Minutes 1 Hour 2 Hours 4 Hours 6 Hours 12 Hours Daily Sync on Wifi only Only sync while on wifi Sync Recently Added Automatically cache newly added albums Sync Starred Automatically cache songs, albums, and artists which are starred Show Sync Notification Show a notification after new media has been synced Optional Menu Options Show Now in menus Show Shuffled in menus Show Play Next in menus Show Play Last in menus Show Download in menus Show Permanent Cache in menus Show Delete in menus Show Star in menus Show Share in menus Show Rating in menus Browse By Tags Browse by tags instead of by folder structure. Requires Subsonic 4.7+ Disable Exit Prompt Exit the app immediately upon pressing back from the home screen Override System Language Display app in english even if the system language is something DSub has a translation for. May need to clear the app from memory for changes to take affect. Drawer Tabs Song Press Action Play only that song Adds everything in the album to the Now Playing Queue Adds song as next song Adds song to end of Now Playing Queue Large Album Art Display albums with large album art instead of in a list Admin Enabled Whether or not to display the admin listing in the pull out drawer Replay Gain Whether or not to scale playback volume by track and album replay gain tags Read from tags Smart detection Album tags Track tags Replay Gain Pre-amp Songs without Replay Gain Casting Use device proxy Stream everything through the device as a proxy. This gets around issues such as using self-signed certificates. Rename duplicate tracks Rename duplicate tracks to the original filename so you can tell them apart. Start on headphones Start when headphones are plugged in. This requires the use of a service which starts on boot up to check for the headphone plug event even when DSub is not running. Color Action Bar Color the action bar and status bar or leave them alone Shuffle By Album Shuffle order of albums Shuffle all songs together Stream original Stream original files where supported by cast device Heads Up Notifications (5.0+) Show playing notifications as Heads Up notifications (Android Lollipop+ only) Cache While Casting Cache currently playing songs while casting DLNA Enabled If you are having battery drain problems on Android 7.0 try turning this off Rewind Interval Fast Forward Interval Shuffle By Start Year: End Year: Genre: Pick a genre Failed to create share %s Expires: %s Never Expires Deleted share %s Failed to delete share %s No expiration Expires: Updated share information for %s Failed to update share information for %s Share via Delete Share Username: Email: Password: Successfully created new user Failed to create new user Enter a valid username Update Permissions Successfully updated permission for %1$s Failed to update permissions for %1$s Change Email Successfully changed email for %1$s Failed to change email for %1$s New Email: Enter a valid email Change Password Successfully changed password for %1$s Failed to change password for %1$s Current Password: New Password: Enter a valid password Delete User Successfully deleted %1$s Failed to delete %1$s Confirm Password Entered password is wrong Permissions Music Folders Scrobbling allowed Administrator Change settings Download original files Upload to server Change cover art Add comments Manage podcasts Stream music Control jukebox Manage shares Convert videos Use Last.FM feature A network error occurred. Retrying %1$d of %2$d. This program requires network access. Please turn on Wi-Fi or mobile network. A network error occurred. Please check the server address or try again later. Resource not found. Please check the server address. A problem occurred communicating with the server. Please check the server address and verify that you can connect using a regular browser on your device. Contacting server, please wait. Incompatible versions. Please upgrade DSub. Incompatible versions. Please upgrade Subsonic server. Wrong username or password. Not authorized. Check user permissions in Subsonic server. Got %d artists. Server error: %s Scanned %d entries Select folder All folders Equalizer Enabled Select preset Bass Booster Voice Booster %d dB %d mille DSub (4x1) DSub (4x2) DSub (4x3) DSub (4x4) Touch to select music SD card unavailable No SD card 0.00 GB 0.00 MB 0 KB 0 B Change Log What\'s New OK More… Send a message Version %s Start playing Start playing in Shuffle Mode Tasker -> Start DSub Start in shuffle mode: Shuffle start year: Shuffle end year: Shuffle from genre: Toggle offline: Do Nothing Song Details Album Details Podcast Details Playlist Details Artist Details Internet Radio Details Podcast Status Artist Album Track Genre Year Server Format Server Bitrate Cached Format Cached Bitrate Size Length Bookmark Position Rating Description Owner Comments Song Count Public Created Title URL Error Message Author Email Version Files Cached Permanent Cached Used Space Available Space %1$s of %2$s Song Position Updated Starred Last Played Expiration Played Count Stream URL Home Page DSub cannot function without the ability to write to storage No songs One song %d songs One song scheduled for download. %d songs scheduled for download. One song added to play queue. %d songs added to play queue. One day left of trial period %d days left of trial period