Problem scenario
You have a web-based email account, and you cannot send an email. You cannot save a draft of the email. You get "Error when communicating with server" in red. What should you do?
Solution
Delete the images/graphics of the original email or in your message. This usually happens when the sender had graphic intensive content, and you are trying to respond.
Use just text -- not HTML. Delete pictures etc. If you can delete the original message, that may be best. Now try to send or save the draft.