- π¬π§United Kingdom aaron.ferris
I've come across this recently as well, although I can't add specific steps to reproduce I can say that this affected several modules I was enabling via Drush. Ban, twig_debugger as well as a custom module that was defining its own config form. All 3 settings forms would give the result from the opening post (class does not exist).
Clearing the caches via Drush didn't help me, but clearing the caches via the UI did..... it's super odd. Adding this comment for anyone else who might come across this issue. Try clearing the site caches via the UI.
- π¦πΉAustria tgoeg
This sounds familiar.
Sometimes, problems like this even make you unable to use the UI, so no way of clearing the cache via the UI.
I don't know why there is a difference, but
drush -l <site> php:eval "drupal_flush_all_caches();"
is the function the UI triggers. This can be run from the CLI as well and saved my day a few times already.