How do I fix this error upload error?

How do I fix this error - Uploading items(s) to folder ‘[email protected]/[email protected]/’ failed due to the following error: Invalid email for the organizer.

If this is related to a calendar event, I would check that organizer of the event has a valid email address.

Or, if it is an online calendar, you could remove the account from eM Client and then add it again.