What steps will reproduce the problem?
1. Do a fresh install of Prosody 0.9
2. Do a fresh install of mod_admin_web
3. Create user, set user as admin in config file
4. Set c2s_require_encryption to true
5. Restart Prosody
Go to http://example.com:5280/admin. After pressing "Login" button nothing will happen, and no errors on page or in the logs.
Go to https://example.com:5281/admin. Everything works fine.
Tested with both internal_plain and internal_hashed authentication settings.
I guess this happens because my settings do not allow non-TLS auth. The bug here is that login fails silently, with no error messages.
titlemod_admin_web: Login silently fails if HTTP used instead of HTTPS