Symfony version(s) affected

6.3

Description

Currently is used method bodyToString of MIME attachment, which generates base64 string of body split into chunks by max-line-length for MIME. This is not correct behavior for Mailersend API which requires not-splitted base64 encoded string of body.

How to reproduce

Send email with attachment via Mailersend API integration. Error occurs if base64 encoded body string of attachment has more than 76 characters. Mailersend API response with: The value must be an Base64 encoded string.

Possible Solution

No response

Additional Context

No response