Unable to share files in Outlook

Hello,

good day for everyone
i have this issue for few weeks now. if im working on a new file, and i would like to share it via email(outlook), im getting the same error message: general mail failure. quit microsoft excel restart the mail system and try again.
if i would like to start a new mail, then add the file - there is no problem. but if work on excel, and i would to share - i will get this message. anyone know's why is that? and how to fix it?

i tried to many things... nothing worked.

thanks
shahar