Hey there smartest!
I am sorry to hear that you are experiencing this inconvenience. Have you also tried relogging and then seeing if you could surf afterwards?
yes i tried relogging twice and still couldn't surf onto water
I have got the required bagde and pikachu learned surf, still cannot surf on water. Talk/interaction with near water, and it had table ask you want using surf or not. Nothing happened after clicking 'ok'.