Workflows failing with error "The e-mail message cannot be sent. Make sure the outgoing e-mail settings for the server are configured correctly"

Hello,

Can someone please provide me with an insight on this. My workflows are failing (both out of the box and SPD developed) with the error "The e-mail message cannot be sent. Make sure the outgoing e-mail settings for the server are configured correctly." I have checked my email settings configuration and all seems to be correctly configured.

Recently, my company migrated to Exchange online. could this be the reason?

Any help with this will be greatly appreciated

Thanks