Hi - We are using EASendMail component (7.9.0.9) with MS Graph in a VBA application.

One of our clients is getting this error occasionally: {"code":"ApplicationThrottled","message":"Application is over its IncomingBytes limit."}} when they send emails with attachments, and after checking the number of email sent before the throttle kicks in, and the size of the file attached, it looks to me like they are being throttled prematurely because the data being sent is roughly twice the size it should be.

This is what I see when I send a single email with a small attachment (354kb):

Log Info: 6/4/2024
https://graph.microsoft.com/v1.0/users/xxxxxxx/sendMail  ...
[13:02:50.562] [C] Posting data [size:678660] to server ...
[13:02:50.917] The email has been submitted to server successfully, task completed.

When the email is received, it only has the single attachment (as expected), and Outlook reports the email item size as 386kb, also as expected.

Why is EASendmail sending data (or reporting that is sending data) that is twice the size it should be?

By the way, I've confirmed the same behavior using v7.9.2.1 on my dev system.

Thanks for any assistance.

Ann

Because the attachment data will be encoded as base64 in rfc822, so 387 becomes 387 * 4/3 = 514, then before uploading the data to graph api server, the entire data is required to be encoded by base64, so 514 becomes 514 * 4/3 = about 680.

>> {"code":"ApplicationThrottled","message":"Application is over its IncomingBytes limit."}}
I guess that is because the customer sent multiple emails in a short time and the entire bytes of messages are out of the limit.