Does the cable work with other adapters? That’s the next isolation step to determine where the issue is coming from.
assuming the cable is fine on both ends, and works with other charging blocks, we wouldthe. Look at the charger itself.
inspect the prongs that plug into the outlet, and test with other outlets. It could be a loose outlet, or another electrical issue with the outlet. That is why we would try another known Good outlet.
if that is not the issue you want to look at the cable port and make sure it is clean, and free of any debris or breaks.
at that point, the next step comes to using a multimeter to test the power coming out of the charger to make sure it is consistent and correct for what it should be outputting.
my expectation is it is either the cable, or where the cable plugs in, or the wall outlet.
if the charge is throwing incorrect voltage, wattage, or amperage it could behave in the manner you describe. Most likely it will simply need replaced, as there generally is not a way to work on them safely, and there are not user serviceable parts inside.
trying to save a few bucks by patching it yourself when you don’t know what you are doing is a potential fire hazard, and could further damage the device, cable, or outlet. Not worth it.