BTW. npm audit give me whole bunch of so called "security issues".
No, now just one ...
npm audit fix could not fix these - so how can that be fiexed?
$ npm audit
# npm audit report
Cross-Site Scripting - https://npmjs.com/advisories/882
No fix available
1 moderate severity vulnerability
Some issues need review, and may require choosing
a different dependency.
there was a problem with old plugins.
For the future I wold suggest to list all active used plugins.
Then disabling all of them and the update the forum.
If eveything is ok, update the plugins step by step to see if something goes wrong.
Thanks for yopur help. 👍
In the future I have to read the error messages more carefully.
The "bad" plugins were mentioned there 😉