yep, repeatedly

Same for me

It basically means just what it said. I'm not sure what it's referencing in particular but I am guessing the game connects to some online component who's certification has expired and that is triggering the notification. Considering the developers of this game moved on quite awhile ago, this isn't really surprising and is nothing to worry about.

There's even a chance that they will notice and correct the issue because even if they are not working on the game anymore, they are maintaining the servers the game uses and due to that, end up realizing and renewing the certification.

You could think of it like this too. You forget to renew your driver's license and so it expires, it doesn't mean you forgot how to drive a car or anything, it just means your certification has run out. Just in this instance, it's not a "crime" for a web service to be acting without a proper certification but it will keep working just fine.

Somebody forgot to renew a security certificate somewhere on the server backend.

Hopefully it's something that someone notices and fixes, otherwise I'll probably stop playing this.

Ive blocked it not knowing what is it for, now the game doesnt starts

For windows users ( :))) ) certmgr.msc in start menu, look for "Go Daddy Class 2 Certification" -- in -- "Current User\Third-Party Root Certification Authorities\Certificates" with the sweet "Certificate Manager" if you managed to disable it in the first place.