@MattiaM 

Hello, please this article to do some troubleshooting first and provide us with the information needed. 

https://community.tp-link.com/en/home/forum/topic/176410 

And then we will be able to do further analysis and find a solution. 

Thanks in advance. Merry Christmas. 

@Kevin_Z 

Hi Kevin_Z,

thanks for your quick answer, below information requested

• Firmware Version:0.4.0 0.9.1 v0057.0 Build 170308 Rel.62615n 
   
• Hardware Version:Archer VR600 v1 00000000 
   
• I changed manually the DNS (as indicated in the error message)

• I'm in Italy and my ISP is TIM, 8Mbps bandwidth paid. Here a speed test
  
   
• Symptoms of the intermittent connection: internet connection doesn't work both in wifi or cable mode woth the error message "Please configure your DNS server manually" on the router main page. Sometimes rebooting or switching off the router the issue seems to be solved but it usually reappears in a few minutes. Thinking about a wifi channel problem I tried to change the SSID name and the channel but the issue is still there. Here a screenshot of DSL advanced setting when the router is working correctly
     

Let me know if you need more information!

Many thanks

Sincerly,

Mattia

@Kevin_Z

and this is the DSL advance setting when router is not working (DNS error)

@Kevin_Z 

Hello,

I sent to you all information requested few day ago, do you have any news or there are not solution to my problema?

Many thanks

Mattia

@MattiaM 

Hello, sorry to respond late. We tried to do a test at our end but not able to duplicate the same issue. 

Back to your case, it is suggested to enable bandwidth control to give it a go. Below is the instruction: 

https://www.tp-link.com/support/faq/2176/ 

Note: The model mentioned is different, while the steps are the same. 

Please set the total Downstream/Upstream Bandwidth lower than the actual bandwidth you paid. 

And then you can add your devices into the controlling rules if possible. 

May it help and have a nice day.