Yonke imikhiqizo Isithangami Sokwesekwa

It has been observed that when a user uses the Firefox browser and tries to download a DDD file, the file format is .pdf instead of .ddd. In the devtools, it was observed that the content-type is text/plain in the response to the request. I changed the content-type to application/octet-stream, but the error still persists

I am struggling with Gmail and Yahoo mail account in TB these few days. I hit almost the same errors from both. I generated app password for Yahoo mail, and put it in when setting up new account. For connection security: SSL/TLS For authentication method: tried with Normal password, Encrypted password, and OAuth2 However, I am seeing the expected authentication window pop up when trying the OAuth2. For all three authentication method: errors are always the same --- unable to connect to your IMAP server. I've followed another instruction to change maximum number of server connections to cache into 1 or 10. Error messages were the same imap one. So, what should I do/try for next?