Hi @ovidijus 👋

Sorry to hear about the slowness in your WordPress site.

This error typically means WordPress trying to connect to the update server in the background, but couldn’t. This could be due to a simple internet connection issue, or may be the server is offline. This connectivity issue, which usually resolves itself after a while.

If not, try contacting your web hosting provider and escalate this issue with them. They might be able to pin-point the cause of the problem.

Also, review this tutorial – which might be of help: http://www.wpbeginner.com/wp-tutorials/how-to-fix-secure-connection-error-in-wordpress/

I hope that guides you in the right direction

No problem, @ovidijus! Feel free to report back if the problem persists!