The problem is macOS version (if the forum system identified it properly as 10.10 Yosemite). You need to update it.
If you bought it new in 2014, it might be a 2014 or a 2013 model. Both of 'em can run up to macOS Big Sur.
See this list for models and versions compatibility https://eshop.macsales.com/guides/Mac_OS_X_Compatibility
So, to try updating:
First check the model of your Mac here Find the model and serial number of your Mac - Apple Support
Now Update macOS on Mac - Apple Support
If it doesn't work, try these steps first
How to reset the SMC of your Mac - Apple Support
Reset NVRAM or PRAM on your Mac - Apple Support
Restart holding Shift to enter Safe Mode. Once up, restart normally and try to perform the update again.
If it doesn't work either, you can try a bootable installer (I advise to have a bootable installer of a compatible version always around in any case, it can save you from problems during installations/updates)
How to create a bootable installer for macOS - Apple Support
And, of course, have a complete backup on an external drive.