Just an update, I’ve tried upgrading my Mattermost instance to v9.1.4, and unfortunately the error persists. Here are my settings for the “Web Server” section of my System Console. Using nginx as my server, as outlined in the tutorial in my previous post.
Given that I haven’t found many others with this issue, I suspect my configuration. The macOS desktop app allows logins, but given that it seems to be an Electron app, it’s probably handling things very similarly to the web login.
Do the iOS and Android apps manage login credential stuff differently? I have a feeling that’s the kernel of the issue.