Hello Madhur Jain,
welcome to this moderated Azure community forum.
I checked the specification of the Teltonika fmb120 and it seems this device supports 'vanilla' MQTT Brokers.
Although the Azure IoT Hub supports the MQTT protocol, it is limited in MQTT broker capabilities like free topic selection.
Please check out MQTT support of the EventGrid Namespace.
This service is especially designed as generic MQTT broker and supports regular MQTT connections.
For more information about how to integrate this broker in your Azure solutions, check out this blog post.
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