@UttamTiwari1088 

Hi,
To locate the problem, please help confirm the following information.
1. What's the LED status on the Tapo C310 when it shows offline on the Tapo app remotely?

2. Please describe your network diagram, such as the Internet--wireless router)))Tapo C310, etc.? 
What's the model number of the wireless router?

3. You can try to change the DNS server to 8.8.8.8 and 8.8.4.4 on your router and check if it helps.

4. Please check if your router has some special settings, such as firewall, access control, parental control, MAC Filtering, etc.
If yes, turn them off for a try.

5. If you connect your phone to other Wi-Fi networks rather than using mobile data, do you have the same issue?

Best Regards