>>105934580
You're not straightening the wire enough. 2-part crimps will help a little. Filename is a monoprice part number. Passthrough is acceptable as long as it isn't outdoors, but it's kinda shitty and expensive.

Try getting a wire straightener if the cable is extremely difficult and installed such that it can't be thrown away easily. Just the little 3-wheel folding kind they sell at arts & crafts stores. Sometimes with really old / bad insulation the wire will snap before the jacket straightens and you have to throw it out anyway.