Why recently do I get message saying my iMac could not connect with iCloud and I have to sign in

My iCloud connection used to be seamless. Never gave me a bit of trouble. In the past couple of weeks, each morning when I wake my computer up I get a message that says it could not connect to the cloud. I sign in, but I am not even sure it is signed out. I also get this message at other times.

I have my cloud account set to "stay signed in". In the past, even without that setting, I did not get the lost connection message.

Any ideas?

Thanks,

Deanna