Note that the TT-30 to 13-50 adaptors are wired for RV use and will not work with Teslas. That's because the TT-30 is a 120V connector and connects the TT-30 hot and neutral to one hot and the neutral of the 14-50. The Tesla, however, does not connect to the neutral at all.I had trouble with a TT-30 a few weeks ago -- dunno what the issue was, maybe that it didn't have the right ground or something. It worked fine for my travel trailer, but not for the car for whatever reason ("check charging equipment"). So be careful about RELYING on this until you've demonstrated its capability.
So the Tesla TT-30 to 14-50 charging adaptor must connect the TT-30 hot to one 14-50 hot, and the TT-30 neutral to the other 14-50 hot pin. And such a Tesla charging adaptor must NEVER be used for any other purpose than charging Teslas.