Is this the cable running to the motor? If so, it may be the hall sensors are buggered if disconnect happened while riding. If the plugs are coming loose, then something is wrong with at least one side of the connection and should be replaced (either the wiring harness side or, more difficult) the motor side. Either way, if you can’t do that, an electrician should be able to, once you have the parts.

If the problem is in the connector (could be elsewhere as some have suggested) and if it’s like the one in the pic, then it’s likely gone. Possibly corrosion, or a defect, or loosened female side, etc. This is a HiGo connector and they’re generally very robust. The male side is likely fine. You could replace the female or both sides by buying an extension of the same HiGo type (number and type of pins), cutting it in the middle, cutting the existing connectors, then splicing the newly cut connector-wire pairs to the respective sides. You’ll have to ensure the pin arrangement is the same as in the original cable using a multimeter. If all of this sounds overwhelming - get in touch with someone who is familiar with wiring and soldering. It’s an hour tops for a person with the right tools and materials. Cutting both connectors and just splicing the wires together is also an option as some have suggested. That might be easier to do if the cable color coding is the same on both sides, but that’s far from certain so I’d say the same work for matching the pin arrangement applies.