How to reset WN3000RP V3

Hi I have WN 3000RPv3 extender which I am using without any issues with to extend my internet range. Now I bought a new 4g router and need to re configure this device to extend that new 4g router.

facing issues as listed below.

1. When accessing www.mywifiext.net page after connecting to the device which is publishing wires network of old AP, this page is seeking login credentials. I don't remember the same as f at all I had registered 2 years ago. Neither there is any forgot user ID & forgot PW links to reset the same.

2. Not able to reset to factory reset status. Tried pressing factory reset button with a pin. Not sure if it needs a long press etc.

help appreciated from any experts.

thanks,

raj