The cab's In connector doesn't work with a brown cable. The cab's Out connector does work with a brown cable.
well, my guess is use it a bit and it will also stop working. it took a year of use for your original connector to start cutting out, right?
as Andy already said, your best bet is just avoiding the brown/green plugs. the blue ones work reliably.
he's a respected engineer who had troubleshooted this exact problem due to customer complains (albeit, for a different company) and come to a conclusion, new plugs are the ones to blame: they just don't work good with the combo jacks. other plugs made over latest 40 years work good, but the brown/green ones don't. that's it, really.