Read Receipt causing constant error - operation would change object type

When sending a read receipt I get the following message in an operations\errors window.

An Error occurred - Sending email failed with an error: Operation would change object type, which is not permitted.

So I choose ignore and now I get the error every time I send and receive

I had this happen before so deleted the whole cache and settings are started again … until it reoccurs

There is nothing in the outbox - it looks like the read receipt is hanging - how do I clear it, I do not want to keep refreshing the cache and reset the settings !

No response from anyone … ??

Hi, can you tell me what email provider and protocol do you use?


Office365 via the default selections

please go to Tools - Accounts - your account and tell me what tabs do you see.