iCloud Web Mail will not load messages, delay in deletions, slow functionality

When I click on a new message in iCloud webmail, 90% of the time i receive an error message that says, "Cannot Load Message. This message cannot be loaded at this time. Try again later."

This is only happening at the browser level, not in the mail app on iPad or iPhone.

Also, when deleting messages, sometimes the messages "grey out", but then don't delete. Other times, they take minutes to delete.