Dear customer,
thanks for your question and welcome to Digi Forum.
Please check this guide about IP Passthrough: https://ftp1.digi.com/support/documentation/AN_38_IP_Passthrough_On_TransPort_Routers.pdf
If still doesn't help, please send us an email to tech.support@digi.com to create a case, providing the IMEI of the unit as well as a complete debug.txt file so we can check the configuration.
Thanks,
Digi Technical Support