To unlock this Apple Watch, enter the Apple ID and password that were used during set-up. m•••••@gmail.com. I don’t remember the password what can be done to resolve this issue

If you forgot your Apple ID password

Or;

You can ask apple to remove the activation lock online on this page;

Remove the Activation Lock Here.

Or this;

If you can't remember/gain access to the apple id that paired the watch to the phone.Take the watch and it's receipt with the serial number along with some photo id and any other proof of ownership to an Apple Store and request that they remove the Activation Lock for you.