I’ve seen some charging can hoses and even some cheap A/C gauge sets that would not fit 134 fittings no matter what. If it won’t fit then it has to be a matter of poor construction of the hose fitting or you are not holding your mouth right. It’s not stripped.
Pressure escaping from the port on the car or pressure escaping from the can of refrigerant? You do know this kind of thing comes with the potential for serious injury; right? No goggles could leave you blind if things go wrong quickly.