Exceeded storage allocation. The server response was: 4.3.1 Message size exceeds fixed maximum message size
Modern SMTP mail servers have a configuration variable to set the maximum allowed message size. This defines the largest amount of data the mail server will accept in a single message. If you're trying to send a larger message, the server will reject it. You have quite a few options, however:
- Compress the attachment to reduce its size (e.g. using zip)
- Change the maximum message size limit on the server, but this requires admin access to the server
- Break your message down into smaller chunks, where each chunk is smaller than the server limit.
- Use a different mechanism/protocol to transfer the attachment.
You can't "fix" that. This seems like your server just doesn't allow you to send such huge attachments. Unless you've got control over the server and are able to change that limit there's nothing you can do. Only alternatives I could think of would be providing the attachments through http or ftp and linking to the attachments instead.