[Solved] file_get_contents failed to open stream

Hello everyone,
when I perform enrolments or unenrolments I see a bunch of lines like this coming:

Warning: file_get_contents( mysite.com/joomla/index.php?option=com_j...server&format=xmlrpc ): failed to open stream: HTTP request failed! HTTP/1.1 500 Internal Server Error in /var/www/vhosts/mysite.com/httpdocs/moodle/auth/joomdle/auth.php on line 565

I find how the operations (enrolments/unenrolments) are correctly executed though.
I've read many posts of people facing a similar problem but the solutions were all different. My server situation looks fine, the system check is all green. I dunno if it has anything to do with it, but the red. SSO is off.

Any hint/help will be apreciated.
Thanks in advance.

It is giving an internal server error. You should check your logs to get more info.

Thank you Antonio for your answer.
My checks you mean the notes under my Notification, in Moodle? Cause nothin is there, and all the joomdle flags are green.
And actually what bothers me is that enrolments work fine.

No, I mean apache error log.

Sorry, you're right.
So, I've read the log file and I saw that there are always the same 4 errors, for every enrolment/unenrolment

PHP Warning:
require_once(/var/www/vhosts/mysite.com/httpdocs/joomla/components/com_community/libraries/core.php):
failed to open stream: No such file or directory in /var/www/vhosts/mysite.com/httpdocs/joomla/administrator/components/com_joomdle/helpers/groups.php on line 314

PHP Fatal error:
require_once(): Failed opening required '/var/www/vhosts/mysite.com/httpdocs/joomla/components/com_community/libraries/core.php' (include_path='.:')
in /var/www/vhosts/mysite.com/httpdocs/joomla/administrator/components/com_joomdle/helpers/groups.php on line 314

PHP Warning: file_get_contents( mysite.com/joomla/index.php?option=com_j...er&format=xmlrpc ):
failed to open stream: HTTP request failed! HTTP/1.1 500 Internal Server Error\r, referer: mysite.com/moodle/enrol/self/unenrolself.php?enrolid=71

in /var/www/vhosts/mysite.com/httpdocs/moodle/auth/joomdle/auth.php on line 565, referer:
mysite.com/moodle/enrol/self/unenrolself.php?enrolid=71

It seems like it's searching for this com_community component (community builder?), that I actually never installed on my Joomla.

I found someone with a similar problem and it looks like they solved the problem modifying some PHP file in their system. But I didn't touch any PHP file in mine.
Is it possible that there is something with a wrong configuration?

The component is Jomsocial.

If it is looking for it, I guess you have enabled some configuration for it. Re-check your joomdle config in joomla and moodle, and disable any Jomsocial integration.
It seems you enabled jomsocial group integration in Joomdle in Moodle.

Thank you Antonio and yes: I found the three
Jomsocial activities
Create Jomsocial groups
Delete Jomsocial groups
that were set to yes (actually I'm pretty sure that I didn't but ok).
I changed them to No and it went fine.