The only way to know for sure is to call. If you can put up with the long hold, the agents are generally quite competent.

I have had quite a few examples of perfectly logical and legal connections being denied, possibly because of some quirk or restriction in AMC’s routing rules. Sometimes it could simply be the reverse married segment logic at work, as mentioned above. The weirdest issue I had was YVR-TPE-SIN in J not being bookable, but YVR-TPE-SIN in J connecting to Y worked some very odd reason.