I realize you have checked the foot switch settings already but have you run the pedal Settings/Footswitch/Footswitch Detector and if so what does the display show for Test Completed?
I’m going to guess that there is no firmware problem as I have tested the pedal with firmware 4.0.1 and it works as expected for both switches. The indications are that you have either a problem with your TRS cable or the Footswitch Input connection on the side of your pedal is not making electrical contact with the cable.
If your pedal is still under warranty, you could talk to the dealer you bought it from and see if they will exchange it.
If your pedal is no longer under warranty, remove the bottom plate from the pedal, insert the TRS cable and check that there is contact with the tip and ring of the patch cable. If not, gently bend the prongs so that they seat on the cable jack. As an alternative, you can try gently spraying a little bit of DeOxit contact cleaner on the pedal input jack.
If your pedal is still under warranty, contact Support, firstname.lastname@example.org for help.
Once you’ve tried all of the suggestions users (and Support) have offered and you still cannot get it to work properly, you might want to take your pedal, patch cable and remote foot switch to an electronics repair shop for diagnosis and repair.
Hope you can get it working again.