A third-party application is having issues trying to send messages with MSISDN as the title. The SMSC blocks it.
Capture SMPP trace and analyze
Capture the SMPP trace of the issue: Execute the following command as root user on each of the Traffic Elements:
tcpdump -i any port 9500 -s0 -w /var/tmp/`hostname`_Test.pcap
After the test messages are sent, you can stop the capture with ctrl+C.
Open the trace using a tool like Wireshark to analyze it.
Fix data coding configuration
Check for a data coding configuration issue, as resolved in this solution article.
Contact Support with relevant logs
If it is not a data coding configuration issue, submit a support request with all the following information (from the Traffic Elements, not the MGR):
Traces from all traffic nodes as already explained above.