In reference to this older issue (link below), I’m seeing the exact same thing happen with the most recent version of SAP Concur on iOS 18.3.

When selecting a receipt from Photos to upload to Concur, using the “forward to Concur Mobile” option in iOS, the Concur app attempts to save it to Concur Receipts, but doesn’t the send to complete and fails without error.  It’s easily reproducible and I have others experiencing the problem.  Does not affect the latest Android client.  See link below for the same problem occurring back in March of 2023.

https://community.concur.com/t5/Concur-Expense-Forum/Can-t-upload-send-photo-to-concur-mobile-app-to...