The Battle.net integration has two major issues.

1) It's no longer syncing games. Ownership of new games is not reflected in Galaxy. No idea how long this has been happening, but it's come to the fore with Diable IV.

2) Every time I reboot or restart Galaxy, I need to log in again. It's not a massive problem, but it is very annoying.

Does anyone know how to fix this, or is it just another casualty of Galaxy's neglect?

Yeah, I have the same issue.

Same issue here. It's been happening for a few weeks now.

It's working fine here. Try updating to the latest Galaxy client recently released or even delete everything and install anew...

Yep, not working, it connects, but after I restart galaxy, no more...

Same Problem here.

Same here!

I am also experiencing this.

have this issue too
bought Diablo Resurrected > is shown
bought Diablo 4 > not existent

Blizzard never disappoints its fans...

What does Blizzard have to do with this???

does anyone have a solution?

I took a look into the plugin code.
There are currently only these games supported:

BATTLENET_GAMES = [
BlizzardGame('s1', 'StarCraft', 'S1'),
BlizzardGame('s2', 'StarCraft II', 'S2'),
BlizzardGame('wow', 'World of Warcraft', 'WoW'),
BlizzardGame('wow_classic', 'World of Warcraft Classic', 'WoW_wow_classic'),
BlizzardGame('prometheus', 'Overwatch', 'Pro'),
BlizzardGame('w3', 'Warcraft III', 'W3'),
BlizzardGame('hs_beta', 'Hearthstone', 'WTCG'),
BlizzardGame('heroes', 'Heroes of the Storm', 'Hero'),
BlizzardGame('d3cn', '暗黑破壞神III', 'D3CN'),
BlizzardGame('diablo3', 'Diablo III', 'D3'),
BlizzardGame('viper', 'Call of Duty: Black Ops 4', 'VIPR'),
BlizzardGame('odin', 'Call of Duty: Modern Warfare', 'ODIN'),
BlizzardGame('lazarus', 'Call of Duty: MW2 Campaign Remastered', 'LAZR'),
BlizzardGame('zeus', 'Call of Duty: Black Ops Cold War', 'ZEUS'),
BlizzardGame('rtro', 'Blizzard Arcade Collection', 'RTRO'),
BlizzardGame('wlby', 'Crash Bandicoot 4: It\'s About Time', 'WLBY'),
BlizzardGame('osi', 'Diablo® II: Resurrected', 'OSI'),
BlizzardGame('fore', 'Call of Duty: Vanguard', 'FORE')
]
CLASSIC_GAMES = [
ClassicGame('d2', 'Diablo® II', 'Diablo II', 'Diablo II', 'DisplayIcon', "Game.exe", "com.blizzard.diabloii"),
ClassicGame('d2LOD', 'Diablo® II: Lord of Destruction®', 'Diablo II'), # TODO exe and bundleid
ClassicGame('w3ROC', 'Warcraft® III: Reign of Chaos', 'Warcraft III', 'Warcraft III', 'InstallLocation', 'Warcraft III.exe', 'com.blizzard.WarcraftIII'),
ClassicGame('w3tft', 'Warcraft® III: The Frozen Throne®', 'Warcraft III', 'Warcraft III', 'InstallLocation', 'Warcraft III.exe', 'com.blizzard.WarcraftIII'),
ClassicGame('sca', 'StarCraft® Anthology', 'Starcraft', 'StarCraft') # TODO exe and bundleid
]

Diablo 4 is not supported by the plugin and needs to be added in code (and so does any other new game). If it's not in the list, the game is not imported although the API response from Blizzard correctly includes the game data of D4, I checked that.

I don't know why it is developed like this, I need a further look into this. It seems that the uid (seen in the lines like 'diablo3' for Diablo 3) needs to be set correctly, otherwise the installation or play button is not working.

https://epicorium.com/

Same issue here