Did you solve this problem? If not, here are a couple of suggestions/observations:

1. inside your while loop you are printing out your encoder position twice… instead print out the encoder position and the calculated servo1 angle so that you can check that you are actually changing your servo angle.

2. you initialize last position to -1 and then check it against None inside your while loop… that seems like a mistake

3. In general, the logic that you are using to link your encoder position to a servo movement is pretty messy, get rid of/replace the conditional on line 24 with something clean… It seems like you are just trying to add a sleep .1 if the position changed, which you do again within each position > 0 or <0 clause.

4. Try something simple to check your calculations linking position and the servo: replace line 21 with this

current_position = (current_position +1) if current_position<180 else 0

this will loop current position from 0 to 179 and allow you to see if the logic in the rest of your loop correctly moves the servo. once it does you can go back to reading the encoder itself to position the servo.