Cause
You can get this Uptime Monitoring error in your Location Fail Log if your web server does not support any of the current SSL protocols.
For instance, if your server only supports TLS 1.0 but does not support TLS 1.2 or TLS 1.3.
This error gets triggered even if you’ve disabled “Verify SSL Certificate” under the advanced settings of your Uptime Monitor since the error is related to the SSL protocols used and not the SSL certificate itself.
You’d only get this error if you monitor an HTTPS website; this does not apply to plain HTTP websites.
Fix
It is advisable to upgrade your server and use the current SSL protocols.
Alternative
If upgrading your server to use the current SSL protocols isn’t an option for you, then you can stop receiving this error by changing the Uptime Monitoring target to plain HTTP instead of HTTPS (i.e., if your monitored target is https://your-website.com you can change it to http://your-website.com to get rid of this SSL protocol check).