Downgrade the firmware to version 3.0.4-19.
This version does not have SIP/ALG support.
This *should* allow you to register properly.
There is a Beta version of the firmware: 3.0.5-27.
This version has a SIP tab which allows you to turn off the SIP ALG.
NOTE: The information provided above is from another OnSIP customer offering these settings for other customers with a similar device. OnSIP does not sell nor monitor equipment and/or it’s firmware updates/etc. The settings of routers can change and are out of the control of OnSIP. For best results, reach out to the manufacturer directly.
Optimize your network for business VoIP with the right router