Lets Encrypt Error since June 2021 The server experienced an internal error :: ACMEv1 is deprecated and you can no longer get certificates from this endpoint.

Error : 

The server experienced an internal error :: ACMEv1 is deprecated and you can no longer get certificates from this endpoint. Please use the ACMEv2 endpoint, you may need to update your ACME client software to do so. Visit https://community.letsencrypt.org/t/end-of-life-plan-for-acmev1/88430/27 for more information.

Solution :

sudo apt-get install --only-upgrade certbot

https://community.letsencrypt.org/t/the-server-experienced-an-internal-error-acmev1-brownout-in-progress/148357/7