Solved Issues after upgrade to J4

Well this is odd. While Report configuration says there are wrong collation types, phpadmin shows they are all correct utf8mb4_unicode_ci so what is going on?

and if you look at Kunena Forum: Dashboard under tools > Diagnostics are there errors?

Diagnostics found some problems immediately after upgrade/installation but shows all clear now.

Despite what phpAdmin said about collations, I reset all collations and Report Configuration now shows all collations good.

Problems remain.

It's a shame, but early this morning I could still see the test site, but now the entire site is offline via Joomla.
I could then see that you are working with the tz_jollyany template.
astroid 2.6.6 but
It is not the case that the message remains in memory, so use the clean cache button in the template.
and also tried in the kunena forum: configuration there
Set Forum Offline to yes and save. (clear cache)
then set Forum Offline to No again and save (clear cache)
whether that helps
and there are also no errors in joomla management > database?

That was my first test site (not sure how you found it!) and I've moved the test site to gersoc.uk as I need to use PHP8.1.

Tried your suggestions. Still nothing.

I found your test site because I came across an old question on this forum.
But joomla when Error Reporting is set to maximum and
and in kunena configuration general the Enable Debug Mode on yes also shows no errors?
I find it strange that I see the text on your site and the forum  Normally the forum would not be visible then
that's why I thought about an old override or something.
but otherwise also post from kunena > tools Report Configuration Anonymous