SSR Failure

at start of boil temp was coming up nice when it happened. Have had many brews on my rig with out a hitch. The line side of the ssr was where the failure occurred. By passed the SSR and continued on with the boil at 100%(i really missed the option to dial back the output). Measured the amp draw after the bypass and was in the 20-23 amp range so it was where it should have been and had the correct heat sink(40). the failure was on the input of the line side so my theory is a loose connection that would have generated heat at this point or this how they fail. Had the lp burner back up untill had controller back on line so in the end nothing lost parts on order will be ready for next brew