It appears that what might have happened is that your hosting company updated the version of MySQL because ‘Group’ has become a reserve word in MySQL version 8. If this were my site, I’d contact my host and ask them to change the version of MySQL back or do it yourself in the host’s dashboard. But even if you can do this temporarily, you will eventually need to solve the issue by updating concrete.
Concrete 5.6 and MySQL8 [solved] - Developing with Concrete - Concrete CMS