I am trying to build a non-inverting amplifier using a LM7171 op amp, and I am implementing it with potentiometers as Rf and R2 so that I can smoothly control the gain of the amplifier (and easily check if its working correctly). I am applying +/- 15 V to the op amp. When I adjust the potentiometer's resistance the gain does not change as expected, or noticeably at all. Setup is shown below with traces when the resistances are Rf=Ri=540 Ohm and Rf=1.8 kOhm, Ri=540 Ohm, and as can be seen the gain/amplitude is the same for the different resistances used. The yellow output on the oscilloscope is the output of the amplifier, and the green is directly from a t-connector to the function generator's output.
I have used two different op amps and got the same behavior, so it is not broken, and all connections seem good. I measure the values of the potentiometer so am confident they are as described. Any ideas what might cause this? Thank you in advance for your help.
Setup as voltage follower