I have a TP link router.
Some months ago I tried to reset the password for security reasons. I was halfway entering the new details then decided not to continue.
Ever since then the default password/user (admin) is not recognised by the PC
My PC and tablets/phones still connect.
Today I upgraded my Samsung phone and of course it wont accept the default password.
On line search says a router reset may be the answer, but it appears long winded.
I fear I was having a senior moment. I suddenly realised it wanted my wifi password not the router settings one, so phone sorted.
However I will look at your links as I would still like to get into router settings which at present I can't do.
Thanks for replies.