So you read already all app-lounge threads from say the last 30 days … and thus seen App Lounge FAQ … nothing to add.
You do say Clear cache but it is Clear Storage that is required. In testing I suggest you have all Advanced Privacy (spoofing likely to have an adverse effect on App Lounge) off and Clear Storage and Restart.
(On 2.13.9) Both Wi-Fi and Mobile data permissions are within
Settings > Apps > Show all apps > App Lounge > Mobile data usage.
You don’t mention your full_version_string but 3.1.1-s-20250828521481-official-emerald is available.
Firstly, I was seeing the “Can’t connect” message from the FIRST TIME that I
tried to use the App Lounge, so, even though i did follow the advice, it was
hard to see how there’d be any cached data/storage to remove, unless
something that needs to be removed gets installed when the app itself
was?
Secondly, and happily, updating to eOS to 3.1.1-s-20250828 which
I did before seeing your note about it, and which also saw App Lounge
updated to 2.13.9 has seen things work,following the reboot.
Not clear to me which combination of which activities has got things
working, but it (It being an Anonymous access) is now working.