I finally found a solution, though it is not optimal: I disabled DHCP server *on my router* and enabled it on the extender. So now, all the static ip clients don't have any problems connecting, and...

Thanks @Carl , for your reply. I see what you are saying, but the dhcp server is off on the extender. That's why I say maybe it's a firmware error. Anyway, maybe we should drop this... thanks for...

Carl wrote @Pleyraki That Doesn't make much sense then. There would be no way an extender could affect the true static IP assignment of clients connecting directly to the router with IP assignments...

Carl wrote @Pleyraki What you may want to look at is how the static IPs are configured. If they use MAC ID that could be the cause of this. when connected to an Extender a device's MAC header is...

Extender works ok, but: When the extender is plugged in, other lan clients (not connected to the extender, but wired to the main router) lose connection after 2 days of inactivity. windows on these...