Ah, I'm glad that helped, but it wasn't what I meant
. My fault, I was rushing.
A power-cycle which is what you just did often helps, but a factory reset literally sets the router back to its ex-factory, or usually these days ex-ISP setup, condition. Somewhere on your router will be a small hole labelled "Reset". Inside there is a spring-loaded micro-switch.
You don't turn the router off. Instead, you get something like an opened up paper-clip and press it gently but firmly into that hole. You should feel the switch go down if you start gently. After 5-10 seconds some of the lights will go out and some will start flashing. As soon as that happens you take the paper-clip away and just wait for the router to complete the task. It will end up rebooted.
In the case of Plusnet you may need to re-enter your broadband username and password, (email@example.com IIRC).
Many people, including me, have spent ages like you trying to get an intractable problem sorted out, only to find a factory reset fixes it in 30 seconds.
Kindness isn't going to cure the world of all its awfulness but it's a good place to begin. Daisy Ridley.
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