I agree with the above that you need to replace the auto reset circuit breaker as many of us have done. I originally replaced my 50 amp with a new 50 amp. Worked fine for a year, then started failing again. So, based on what others had done, I replaced my 50 amp with two 40 amp wired in parallel, like this;
I used two short buss bars (covered with heat shrink tubing) from Lowe's. Others used short jumpers made from wire and terminals, or from small copper plumbing pipe straps. Doesn't matter as long as it can carry the current.
Others replaced theirs with a single 80 amp. But those are not as readily available as the 40 and 50 amp. Can be ordered via the web, but the 40 and 50 amp can be bought at any RV parts store and at many auto parts stores.
Here is what one looks like when it goes bad. Pretty cheaply made.
