More info on the vulnerability.
You might of heard of the recent vulnerability in Let’s Encrypt certificates. As per here:
https://community.letsencrypt.org/t/revoking-certain-certificates-on-march-4/114864
You will need to force a new certificate. You can do so by SSHing into your server and then run the following to force a new certificate;
How to force renew your certificate.
"/root/.acme.sh"/acme.sh --cron --home "/root/.acme.sh" --force
If that doesn’t have any result, try running the below method;
acme.sh --cron --home "/root/.acme.sh" --force
Additional Mentions.
You can use the following link to check if your certificate is requiring intervention. Otherwise, sit back and relax, you’ve nothing to do.