You can download the latest version from github (either for Android or Linux), then open the app, click on the settings page, click switch accounts, click add account, click fedia.io, click guest, and then navigate wherever you'd like from there.

Before all that though, I would figure out why your API routes are causing internal errors, such as /api/entries, which should return a list of threads but is only causing an error. If you visit that route in your browser, maybe your PHP logs would have the real cause of the internal error.