Why don't some receipts populate when emailed to Receipts@expenseit.com?

[acandy13]

Hello. I'm an admin here and one of my employees tried forwarding a receipt confirmation for a flight on Southwest and it won't populate either through receipts@expenseit.com or receipts@concur.com. I also tried to forward that same receipt to my own account, and it didn't work, so he is correct. 

I have read that if file sizes are too big, blah blah blah, but this seems ridiculous. 

Is there anything I can do to get receipts@expenseit.com more consistent? Employee is not happy

[KevinD]

@acandy13 was the receipt from Southwest an attachment to an email or were the receipt details in the body of the email? 

I'll await your reply.