MY FENDER GUITAR AMPLIFIER IS MAKING A HUMMING BUZZING NOISE

sounds like bad caps and maybe a failing output transistors. Use Deoxit contact cleaner too.

Does it still have a hum/buzz when NOTHING is plugged into the INPUT? If so, you MAY have a tub going bad. If the noise is only there when you have your guitar/effects, etc. plugged in, then the problem is the guitar grounding or effects faulty...
FIRST: When the amp is "cool", UNPLUG THE AMP POWER CORD FROM THE WALL! ! ! ! Then CAREFULLY remove and reseat the tubes one at a time. Be sure to insert back into the socket correctly. You MAY just have a bit of corrosion on the tube "pins"....

SECOND:Don't plug anything into the amp, turn on and warm up. GENTLY tap one tube at a time with a WOODEN pencil. DO NOT USE anything metallic (like a screwdriver....) and be VERY gentle. If the noise increases or decreases, you probably have a tube going bad...

That's all I have. If this doesn't cure the issue, best take it to a repair shop . . . .

If it's humming when something is plugged into the input, but not when nothing is plugged in, it's most likely the cable. If it hums when nothing is plugged in, the amp is defective and you need to return/exchange it.

try plugging into a different socket if that doesnt solve problem you may need to replace cord. sounds like a loose neutral in socket though.

It doesn't happen often but I suspect that the high gain input jack is defective. With nothing plugged into either input jack part of the signal is grounded and there should not be any noise. It might be that plus a noisy preamp tube. Try swapping the first two tubes to see if there is less noise. Carefully bang your fist or use an insulated tool's handle to hear if the noise changes. It might be an intermittent solder connection as well.

... do you, by any chance, have non humbucking pick ups on your guitar? Just curious...

If the humming ONLY happens when a cable is plugged into the amp, the problem is in the cable or the guitar. Poor quality cables or wrong cables will result in hum. Defective wiring or connectors in the guitar OR having the guitar near a source of magnetic fields will result in hum. We cannot diagnose these possibilities remotely.

Inspect the jack for damage... including solder where it attaches to the circuit board. Common problem when someone trips over a guitar cable. Loop the cable through the handle of the amp to REDUCE the chance of this failure.

There is likely one of three problems:

Blown rectifier in power supply.

Bad filter capacitor(s) in power supply.

Shorted power amp chip causing the riple on the power supply to reach the speaker.

It sounds like a filter capacitor(s) has failed. The electrolytic caps dry out and cease to perform allowing unfiltered power to reach the preamp sections and get amplified.

Being this is tube with high voltages, an experienced person should work on it due to shock danger.

I assume you checked the tubes for shorts as well as emission since a heater to cathode short could cause this as well.