I have been using TP-Link TL-WR740N Wireless Router in my Home to connect Wi-Fi devices. It is working fine for few months without any problem. I went on vacation for 7 days and when I back I noticed that my TP-Link router starting showing unable to resolve DNS Server when I tried to browse any websites. Initially, I thought it is problem with my Internet Service Provider (ISP). So I contacted my ISP (BSNL) to fix this problem. But the settings are fine, and now I am unable to fix this problem. Please, help me how to fix this issue.
Going by your query, it seems that you have not opted for automatic IP generation from your ISP via DHCP. The option for automatic IP address can be turned on from your router settings page which is fairly simple and easy. I will discuss how to complete it,
just follow the instructions given below carefully:
Step 1: Connect your router to your computer via ethernet cable. One end of this cable goes inside the LAN port of your router while the other end goes inside the ethernet port on your computer.
The ADSL cable goes into the WAN port of your router. once the set up is complete, wait for few seconds to let the connection between the two get established.
Step 2: Open your web browser and type in 192.168.1.1 in the given URL field and hit Enter. This will redirect you to the login portal of your router.
Step 3: Enter "admin" in the username field and leave the password field blank and hit enter to get access to main settings of your router. In case your ISP has provided you any SSID & password, enter those credentials.
Step 4: Once on the main settings page, go to DHCP settings or WAN settings whichever of the two is available. In the DHCP/WAN settings tab, you will notice a box for DHCP settings, choose YES.
This will provide your router with automatic IP address from your ISP without you worrying about changing it every few months.
Hopefully, these steps helped you in getting your problem resolved. In case you have any further doubts or problem, feel free to reply and I will be glad to help.
You probably don't have to restart your router to apply these DNS settings.I am sure your issue will get resolved by applying above procedure.
Have a great day. Cheers.