Please test #41300 the fix. Thank you.

after installing #41300 Iget
`Uncaught TypeError: e is null
removeMessages https://localhost/myjoomla4/media/system/js/messages.min.js?7425e8d1cb9e4f061d5e30271d6d99b085344117:1
renderMessages https://localhost/myjoomla4/media/system/js/messages.min.js?7425e8d1cb9e4f061d5e30271d6d99b085344117:1
plgSystemWebauthnLogin https://localhost/myjoomla4/media/plg_system_webauthn/js/login.min.js?d1ff3cc9bf1eec53c199a743e4155462:1
https://localhost/myjoomla4/media/plg_system_webauthn/js/login.min.js?d1ff3cc9bf1eec53c199a743e4155462:1

Same behavior:
If I do a succesful login/logoff and then try to cause a failed login (case 2.) then failure message is displayed correctly. If reloading page after successful login/logoff, error wil happen again.

`

That something different, it not "TypeError: Joomla.renderMessages is not a function" anymore.

Please enabled debug, and post the error trace again.

I can't replicate (Win10; Edge V115.0.1901.188)

hi,
did checks on Joomla 4.3.3. Added "media/system/js/messages.js" to default.php of mod-login. This produced falure:
Uncaught TypeError: messageContainer is null removeMessages https://localhost/media/system/js/messages.js?2dce42a59768e9427f2241dd04344029:306 renderMessages https://localhost/media/system/js/messages.js?2dce42a59768e9427f2241dd04344029:253 plgSystemWebauthnLogin https://localhost/media/plg_system_webauthn/js/login.js?2dce42a59768e9427f2241dd04344029:181 <anonymous> https://localhost/media/plg_system_webauthn/js/login.js?2dce42a59768e9427f2241dd04344029:230 EventListener.handleEvent* https://localhost/media/plg_system_webauthn/js/login.js?2dce42a59768e9427f2241dd04344029:227 <anonymous> https://localhost/media/plg_system_webauthn/js/login.js?2dce42a59768e9427f2241dd04344029:226 <anonymous> https://localhost/media/plg_system_webauthn/js/login.js?2dce42a59768e9427f2241dd04344029:234

#41300 is having same error "Uncaught TypeError: messageContainer is null" using "media/system/js/messages.js" instead of ""media/system/js/messages.min.js""

I think, there may be a problem with DOM or event-handling, as if I do a successful login/logoff and then try to cause a failed login then system behaves correctly. Using a fresh/new page system does wrong.

hi,
may be this might help to fix it:
if you provide a div-element "<div id="system-message-container"></div>" e.g. in default.php of mod-login then the system behaves correctly (will show the error message).

if you provide a div-element <div id="system-message-container"></div>

Then it sound like a bug in your template.
Because this element should be always available.

OK! Will fix this and report bug to developer of template.
Adding lib "media/system/js/messages.js" or using #41300 fixes #41299 - many thanks for your help!

hi,
I found that after installation of joomla 4.3.4 problem reocurred.
I get javascript error " e.renderMessages is not a function"

I had to change/add script in default.php of mod_login:
->registerAndUseScript('messages', 'media/system/js/messages.js');

Please test the fix, then it will be in one of furture version #41300

if the fix works for you, go to https://issues.joomla.org/tracker/joomla-cms/41300
And click this button:

hi,
tested fix - it works! - thank you!