Hi @Iram_Barkat
If you’re able to connect to Atlas from some network and not from others, then it’s highly likely that the issue resides in the problematic network. Perhaps there are some restrictions in your cellular network? I’ve seen many cases where some network disallows connection to non-HTTP/HTTPS ports (80 and 443). Since MongoDB uses port 27017, maybe this is restricted by the cellular network.
Unfortunately there’s not much Atlas can do for this. The best way forward is to contact your cellular provider and asking for clarification about this from their end. Perhaps you can use a VPN product to work around this issue?
Best regards
Kevin