A few different errors

I am in control of the company website that I work for. For a few days the website admin area would not load at all and kept giving me a ERR connection error. After looking on the server and having a play around for any bugs, I couldnt find any problems. The website then started working as usual again but only if I type the URL in completely. But the admin area runs extremely slow and after around about 10 minutes of being inactive, once I go back and click something or refresh the page, the ERR connection code comes back and I have to type the URL in again and start over.

The dashboard overview report also brings up an error saying ‘the firewall of your server is blocking outbound calls. cURL error 28: resolving timed out after 2000 milliseconds’. I have tried disconnecting the firewall completely and refreshing the page but the error message still appears.

I then tried looking at the site health tool and it shows:
Your site could not complete a loopback request.
One or more modules are missing. The optional module – libosodium is not installed or had been disabled. The same for imagick module.
Background updates may not be working properly. Couldnt retrieve a list of checksums for wordpress 5.2.4. This could mean that connections are failing to wordpress.org.
Your PHP requires an update. When I click the learn more button to update the PHP, Cloudlinux pops up saying that the PHP is taken care of and to ignore this error.

I then downloaded query monitor. The error message that appears reads ‘PHP errors were triggered during and Ajax request. See your browser developer console for details.
In HTTP API calls there is a cURL error for my theme plugin. I deactivated the theme plugin which turns my site into code and the issues are not fixed in the admin area. This also appears on a few other plugins but these seem to change every time I refresh or move onto a different page.
I also get the error Certificate verification diabled css (verify=false) in the query monitor overview area.

I have tried deleting the cache and cookies on the site and web browser and tried other web browsers. I have disabled my firewall and plugins to try and figure out which plugin was causing problems but have had no luck. I hope this makes sense!
Thanks