In SAP TM to enable the Logs to be visible for the Key user check errors or any other messages, you need to customize it to be visible.

SAP TM use 2 messages type “Application Log” and “User Interface” these messages refer to transaction data and UI for the Fiori.

Here you can determine the level of logs:

Important: That flag indicated to have the logs of charge in FO/FB to be saved in database.

Also, some assign these parameters to the Users.

• /SCMTMS/MAX_NUM_LOGS – TM Logging: Maximum Number of Logs
• /SCMTMS/TCC_LOG – Switch on charges log
• /SCMTMS/TRIG_EXT_LOG – X = Extended logging for bgRFC trigger processing

This will enable to your user see the messages, i.e in Charge calculation log.

You can check and delete the logs of TM in the Transactions in the SAP GUI:

Check Logs:

/SCMTMS/APPLOG – Display Application Log Entries

You can delete the entries on the Log table /SCMTMS/D_MSGREG – Application and UI message store using the Transaction /SCMTMS/MSG_STORE – Display Message Store

Refer:

2463749 – How to increase TM Message Settings – SAP for Me

3392867 – Running Report /SCMTMS/APPLOG_MASSSTORE in the Background Fails – SAP for Me

Message Settings | SAP Help Portal

Hope that can help you.

Thanks and regards

Rogerio Lima.