Installation and server related problems

One of our admin added content bank with Moodle and this was all working with H5P content, but then it stopped working and giving a 504 timeout error.  Moodle community suggested it is a registration issue with H5P.org,

However, neither the Moodle installation instructions on their site or the H5P instructions on this site detail how / where I set the registration so our courses can connect with H5P.org?

The possible issues mentions registration issues, but it only mentions Guzzle and missing CA cert.

Dear all,

On my WordPress site I have created some h5p quizzes I’d like to embed to other pages outside the site domain. Other users tell me that this is not a problem at all, but on my pages I get the error message that the origin/source website has declined the access. I tried embedding the code on one of my other WordPress pages, but get the same error message. I've checked the plugin settings and also tried to grant access by changing the .htaccess file by adding

Header always unset X-Frame-Options

Using Moodle v3.9, mod_h5pactivity version 2020061500, PHP v7.4.33.
When I add new H5P activity into a course, it results http 500 error in Moodle v3.9.

After checking webserver logs, I see the following error:
PHP Fatal error:  Class core_h5p\\file_storage contains 1 abstract method and must therefore be declared abstract or implement the remaining methods (H5PFileStorage::deleteLibrary) in /srv/www/moodle/htdocs/h5p/classes/file_storage.php on line 37, referer: https://mymoodle/course/view.php?id=123