Certificate and key do not match : Certificate and private key do not match

SYSTEM INFORMATION
OS type and version Ubuntu Linux 20.04.5
Webmin version 2.010
Virtualmin version 7.5 Pro
Related packages SUGGESTED

Hello,

I tried logging into Webmin today. I got the error: ERR_SSL_PROTOCOL_ERROR.
I disabled SLL via SSH. SSL = 0 in /etc/webmin/miniserv.conf file. After that I was able to login to Webmin via HTTP instead of HTTPS. Next I disabled Apache SSL website in Edit Virtual Server for domain which i use for Webmin and Virtualmin.

I am currently unable to restore SSL for this domain.

Edit Virtual Server >> Apache SSL website enabled:

Result is:

Changing IP address of virtual website …
… done

Adding new SSL virtual website …
… certificate and key do not match : Certificate and private key do not match

Updating Webmin user …
… done

Updating Webmin user …
… done

Saving server details …
… done

Applying web server configuration …
… done

Re-loading Webmin …

What can I do?
Thank you.