There was an error updating the certificate: Error when requesting certificate Let's encrypt

Hi All, I tried to apply a new certificate by using certificate manager-New certificate-Generate Let’s encrypt certificate and got this error.

I am able to view the code by directly entering the below address in my browser from an external network pc.

There was an error updating the certificate: Error ‘Requested ‘http://xxxxx.xxxxx.com//.freepbx-known/847afe526c910130345b7910592793a7’ - Failed connect to http://xxxxx.xxxxx.com:80; Connection timed out’ when requesting http://http://xxxxx.xxxx.com//.freepbx-known/847afe526c910130345b7910592793a7

Thanks for help.

FreePBX 14.0.3.6 ‘VoIP Server’