Can only receive emails

In my Comcast email I cannot compose, reply or forward emails. I can get emails no problem. I get the error “An error occurred inside the server which prevented it from fulfilling the request”. Comcast can't seem to assist me. I cleared my cache, tried incognito, a new browser, reset my password, disabled VPN, checked, and 'unchecked allow third-party access', and my storage is not full.  My husband also has a Comcast email account, and he is not having any of these issues.