License check failure See the Debug Guide
Reason: request failed: Post "https://licensing.directadmin.com/start": x509: certificate has expired or is not yet valid: current time 2022-10-26T11:51:22+03:00 is after 2021-09-30T14:01:15Z

The issue is likely due to server CA root certificates being too old.

If you are using Centos 7 which is still supported – you should still be able to update your OS.
Check what is your redhat version with:

cat /etc/redhat-release

The latest centos is 7.9. If you get something older – update your system with yum:

yum update -y

After that – just restart the DirectAdmin service and it should be able to communicate with the licensing server.

If you run CentOS 6 system – no caroot certificate package is available for you. You could mitigate the issue by downloading the file manually with:

curl -k -o /etc/ssl/certs/ISRG_Root_X1.pem https://letsencrypt.org/certs/isrgrootx1.pem

Just restart directadmin afterwards and you’ll be fine.