@Anan_265 

Hi,

Try using another web browser. (Firefox, Internet Explorer, Edge, Chrome, Opera, etc.)

In case you manage to log into the router with another browser, then check if there is a newer firmware version available that you can upgrade your router to.

  @woozle 

Thank you. I solved the problem myself anyways. I enabled TLS 1.0 and 1.1 in Windows "Internet Options settings" and reloaded the router web interface in Internet explorer mode within Microsoft Edge. And then I disabled HTTPS in administrator settings.

Btw, the following is the Software and hardware version of my router:

Following is showing up under firmware upgrade page at official website:

Is there an update available? If yes, which one should I download? I am confused on determining the update availability. My region is India

  @Anan_265 

There is a slightly newer version for the C20(EU) listed on the Worldwide webpage, but it doesn't mention anything about supporting a newer TLS version. You could still try it, though. Sometimes the Release Notes aren't very detailed about the changes that were made.

https://www.tp-link.com/en/support/download/archer-c20/#Firmware

If the latest firmware still doesn't support a newer TLS version, then you will have to keep using one of the two workarounds you've mentioned.