xxx.com:8080 uses an invalid security certificate.

I followed the perfect server tutorial at
https://www.howtoforge.com/tutorial...l-pureftpd-bind-postfix-doveot-and-ispconfig/
to install IPSConfig 3.1 and chose the option to create a secure (SSL) connection to the ISPConfig web interface. Everything is working fine except when I access ISPC (https://wwww.xxx.com:8080) I get an invalid security certificate error. I can add an exception but I would rather fix the problem, particularly as Let's Encrypt is working for sites created within ISPC. Is there any way of fixing this problem?
Thanks,
Cliff

 

Oh, OK, thanks Till. I'll check it out now.

 

Yes, that worked for me, thanks againTill.