Help! Mold in my humidor

Hello fellow connoisseurs of fine tobacco!

Last night, I wanted to take a cigar out of my Klarstein el Presidente humidor and unfortunately noticed that 4 of the 7 cigars I had in there were moldy. Of course, I immediately discarded all the spoiled ones and put the rest in an airtight plastic bag for observation.

So far, I've only been able to find information online about how to clean a traditional humidor. Does anyone have any tips on how to clean an electric humidor after a mold infestation?

I also wanted to ask if anyone has any idea what might be causing the mold? The humidity has been almost constant at 70% for the past few weeks, and the cigars were stored in such a way that air circulation could hardly have been disrupted.