I've been using One Calendar on Mac for years, but it has Sequila 15.7.2 (24G325) on my 2019 iMac.

I have been using One Calendar on Mac for years but it has become totally unstable with Mac OS Sequila 15.7.2 (24G325) on my 2019 iMac which is not upgradable to Mac OS26. It starts up with an error, then asks if it should add Task support and whther you say Yes or No it does nothing and asks you to log into your gmail adress again after which at least teh calendar part works. But if i restart, i get teh same. I am at the pointof deleting it , which is a pitty as i have always preferred it to the Apple Calender. Any options ?