I used to be able to use my Contactless AmEx at Shell with both Verifone and Gilbarco registers. In the past couple months it stopped working at the ones with the Verifone but still works at the ones with Gilbarco.

Hard to understand what is going on.

The Contactless AmEx also does work at Chevrons with older Nucleus registers but does not work at Chevrons with the newer Verifone registers.

I've decided the Verifone registers are the problem.