What FET are you using?
The second FET has an unmarked resistor in the drain connection - what value is it.
That FET also has a 1MΩ source resistor. 270Ω like the first FET would be more like it.

I’m using 2n5457 jfet transistor and the drain is 1.5kohms resistor for the second jfet.

 

Have you tried connecting a different audio signal to the MAX to verify it's working?

 

You do not show how the amplifier is connected.
Here are a couple more problems with your preamp:

 

Have you tried connecting a different audio signal to the MAX to verify it's working?

Nope I haven’t tried that yet. What if I don’t have a different audio signal to try it out. What should I do?

 

You do not show how the amplifier is connected.
Here are a couple more problems with your preamp:

You do not show how the amplifier is connected.
Here are a couple more problems with your preamp:

Thank you, should I put the bypass filter for the 3.3V in parallel or in series? I’ll take out the capacitor and resistor and increase to resistor load and let you know if it works.

 

The preamp should be connected to the MAX this way.
Once you get the MAX working then you can make the improvements on the preamp.

 

The preamp should be connected to the MAX this way.
View attachment 229700

I see I’ll try that, thank you.

 

Thank you, should I put the bypass filter for the 3.3V in parallel or in series?

The bypass capacitor bypasses the 3.3V. Bypass means in parallel. Try 47uF plus a 0.1uF (104) ceramic. They prevent oscillation.
The Adafruit amplifier seems to be very cheap. Maybe whoever made it did not test that it works?

 

It worked! I’m using another amplifier, increased the load and used only one jfet preamp

 

The MAX98306 has a differential output stage. I assume you are not using batteries to power the circuit since you are showing a 3.3 volt supply circuit. I'm also guessing that maybe the ground side of the power supply is connected to earth ground.

If it is and you are connecting the scope ground lead directly to one of the speaker wires you are shorting the output of the MAX chip to ground and "possibly" destroying it. The datasheet says it has output short and current overload protection so maybe the chip is still good.

Put a 0.47 uF or 1 uF capacitor in series with the ground lead when you connect it to the speaker. That will prevent the scope from grounding the output circuit of the chip. If the power supply ground is not connected to earth ground the scope ground lead should not be a problem. However, a capacitor in series with the ground lead is still a good idea.

If the preamp works with another amplifier it will work with the MAX98306.