@Rimi Hi Rimi, 

For TC70 camera offline problem, here are some suggestions: 

1.  Turn off advanced features on router like Parental control / Firewall/ QoS function etc. 

2.  Make sure the camera is receiving a good signal by checking the signal strength of the camera on the APP.

How to check the signal strength: On the APP, go to Camera settings->click the name of the Camera->signal strength

 (You could tap on the Wi-Fi icon to see the value of the RSSI) Please share us a photo of that. 

3. Make sure tapo firmware in tapo app and tapo APP version are both up to date 

4. on Tapo app refresh the device list page by "pull-to-refresh" and see if the camera would be online

Please help proviode some details if issue persists: 

1) Model number of router: 

your network topology: for example,  ISP  modem --- router Archer AX10 < wireless >Tapo C200

2)  Please check the LED status on camera when the issue happens , is it  Red/ Green or Solid on:

3)  How often does camera become offline?

How did camera recover the connection,  do you need to reboot camera or it will recover automatically? 

4)  Please help save the log of camera and share with us: 

How to get the logs:
Step 1: Insert an SD card into the camera.

Step 2: On the APP, please go to Camera Settings -> Advanced Settings -> enable Diagnose. The log file will be stored on the SD card.
Step 3: Let the camera run for some time, wait for the recurrence of the problem.
Step 4: Please plug the SD card into the computer's SD card slot or an SD card adapter. Please send the log on the SD card to us. The name of the file is ‘Diagnose Log’.