Line length limits for email attachments

[rsmolkin]

Hi,

We are getting some bounced emails with the following code:
"smtp; 552 message line is too long"

We use AWS SES service with sendRawEmail, and the email messages have attachments.

I've been going over the structure that builds the raw message for days now, and have added a bunch of new line characters to ensure that no line is longer than 78 characters.

The only potential issue that remains is the actual content of the attachments which is encoded as base64. It doesn't seem that those lines are getting wrapped under 78 or 996 max length character limit. I'm not sure if the actual attachment content also needs to follow that rule, and if it does, how to actually accomplish that, cause introducing new line characters would probably break the actual attachment.

Any suggestions?