Getting error message when trying to send

Hi, hoping someone can help. When sending an email, I get the following error message. I’m also using ProtonBridge which is connected to fine. No issues. Able to recieve emails and a couple emails were sent without error.

[SMTP]Cannot send message (Email body not accepted due to the following reason:
"5.0.0 Error: transaction failed, blame it on the weather: failed to create new parser: message: malformed MIME header line: /9j/4AAQSkZJRgABAgEASABIAAD/7QAsUGhvdG9zaG9wIDMuMAA4QklNA+0AAAAAABAASAAAAAEA

Can you send the same message using a non-Proton account?

Yes. gmail account is working fine. Will need to followup with Protonmail.

Hi, did you ever get an answer from Protonmail? I’m having the same issue. Thanks!