No access to add-in store in Excel for Windows: "Can't reach this page"

(* I don't know if it's the right hub to ask this question *)

In Excel for Windows, I cannot enter the add-in store anymore, here is the message.

`Can't reach this page`, `Make sure the web address https://inclient.store.office.com is correct`, etc.

I used to have this error long time ago. I recall more or less that the problem was due to some VPNs which modified some internet settings. After modifying one check in the internet configuration, the store was back.

But unfortunately I forgot the exact place to amend. I don't use VPNs either.

Does anyone know how to solve that?

PS: The account is validated. https://inclient.store.office.com/ in a browser redirects to https://appsource.microsoft.com/