Hello,
Thank you for your query.
Please check device's server settings> Domain and Port. Make sure device catch GPS fix and sends records. What kind of platform you are using? If TAVL this should not make any difference if it is FMB120 or FMB122, device should appear online. (Might differ data sources which FMB122 has and FMB120 does not).
Best Regards,
Teltonika Support.