@Svantes 

When you have that laptop connected over WiFi, open command prompt and type the following:

netsh wlan show interfaces

Please make screenshot of the output and share it here. 

  @Alexandre. Can you read the file`?

  @Svantes 

Yes, I can read it. 

Authentication is correct. Connection is established. 

Try troubleshooting steps from this article: 

I can't post external links here, so type that URL manually in browser, or google for that article by its headline and author:

"

WiFi Connected But No Internet? Here is How to Solve It Easily

November 23, 2020 by Chantelle Clark

"

Also, because it is office laptop, I would suggest to make screenshot of "weak security" or "outdated security standard" warning, also have that netsh command output and show both to your IT support at work. Tell them that TP-Link mesh you use at home can only support up to WPA2 security - it does not support WPA3. Ask if this is the cause of the issue, and ask for recommendations how to deal with it.

  @Alexandre. Hello Alexandre,

Thanks for your patience. I am currently trying all the different solutions in the website you posted. So far no success

I 

  @Svantes 

If nothing works, it may be possible that your office IT recently placed restriction on WiFi security and force use of WPA3, for example. You should check with them. If it is their new security settings, that will explain why laptop used to be able to connect to Deco mesh before and get Internet access, but no longer.

If this is the case, and they are not flexible in relaxing that restriction, not much can be done with Deco mesh you have. 

Meanwhile, before you get to talk to IT support from your office, if this laptop has Ethernet port - try connecting it with Ethernet cable to Satellite Deco. 

  @Svantes Hello Alexandre!

Finally it works.

I think it was the disabling of fast startup that made it,

Thank a lot for your kind help!

Svante