Unable to connect to iCloud on my mac

Hi, is there any issue with iCloud actually?

I have tried to sign in to iCloud on my iMac but it says that "You can't sign at this time"

Same thing happen on my iPhone 6. As from 2 weeks now, i can't use handoff or sync all my devices.

Can any advise what to do to resolve this issue.

Thans in advance.