Nextcloud Talk on android jumps back to "Server address" screen after "Grant Access" is pressed

Logging in to the standard andoid app of Nextcloud works fine, but when signing in to the Nextcloud Talk app, pressing “Grant Access” simply jumps back to the prompt to enter the server address.

Nextcloud is running behind a reverse proxy, so I’d made some changes to the config.php file to account for that (overwritehost, overwrite.cli.url and overwritecondaddr). I recently removed overwrite.cli.url and overwritecondaddr, and then added overwriteprotocol to https, and that got me to this point. Before making that change, both apps (Nextcloud and Nextcloud Talk) would simply get stuck on the “Grant Access” screen and do nothing.

Also of note: before making those changes, each attempt to log in would create a “warning” entry in the nextcloud log, saying failed login. Now, this process doesn’t create any entries in the log (failed login still creates an entry if the incorrect password is used, but it used to create a failed login entry when clicking “Grant Access” which no longer happens). This makes me wonder if my changes to config.php, while beneficial for the main Nextcloud android app, have somehow made things worse for the Talk android app. Edit: based on testing the incorrect password, I believe this is progress after all…

Any ideas for getting this working?

About my setup: nextcloud 17, Ubuntu 18.04, apache2, php7.3. Talk app version 7.0.1. Anything I’m missing?

Edit: some additional information. I noticed going through this process does add an entry in the “Devices & sessions” section of Security tab of the account trying to sign in, with “[device name here] (Nextcloud Talk)” as the entry name. So it seems the device is communicating with the server and starting a session under that username, but for some reason the app kicks it back to the “Server address:” screen.

Update: Entering the username with different capitalization got around the problem. I came across this post describing a similar issue with the standard android Nextcloud app.

It described it as an android problem (where android is not properly deleting a saved account, but also not allowing you to re-add it) and the suggested workaround was to take advantage of the fact that the android account stored was case sensitive, while the nextcloud account name is not. Thus when I simply capitalized one letter in the account username and signed in, it seemed to work.

From the comments in that thread, it sounds like something the app developers can’t change about the android OS, but for anyone else coming across this post, this was as close to a solution as I could get short of rooting the device and modifying low-level android OS files.