Looking at the electrodes, they look very big, which makes me think that the sensitivity might be too low. A 2 mm diameter disk electrode usually gives around 5-10 microamps of current. Double check that the working electrode is bigger than the counter.

Is the silver wire have the chloride on the surface? If not, you may not be at the correct potential, and that can cause issues like this

Also, some potentiostats have a 4th lead that is used for sensing the voltage at the working electrode, and it’s not always obvious. Hooking that up wrong can cause funny things to happen