Hi Finn,
I always get the same message on all my computers, so, apparently this is a window problem.
This is, in fact, your router's problem, since all of the computer shows the same problem when accessing the router.
TP link explains it here:
https://www.tp-link.com/us/support/faq/2598/
TP-Link's local management uses a self-signed certificate — one not issued by a recognized certificate authority (CA). Browsers flag this automatically, regardless of whether the connection is actually safe. The warning reflects the certificate's origin, not the security of your data.
This is similar to your router.
I hope this information helps. If you have any more questions, don't hesitate to reach out. Wishing you good luck!
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