"0 Call to undefined function getBuffer()" error

Hello,

when someone tries to login with username (=email) and password in CB login module before he's/she's confirmed registration, app crashes with error message mentioned in subject. This is the same when someone tries to login who's never registered before.

Actually after this has happend all new registrations will fail with same error after clicking "register".

As error is very generic where to start to track this down?

Thank you in advance.

Ensure everything is up to date and see if issue persists. If it does enable debug mode and maximum error reporting in Joomla global configuration then provide the full error. Without the path and line number I've no clue where your error is coming from. However, getBuffer() is a part of Joomlas core functionality for outputting the buffer, which CB does not touch. Try purging cache if you've caching enable to see if that clears it as could be a bad cache file.