Unless, the solenoid is generating a huge EMF wave (sound's like an EMI PULSE) and frying everything within 3feet of it....
The interference is coming down a digital pin or via (more likely) the 5v rails...
- Separate the power supply (give it a 2nd USB fed 5v supply if you have to) 2 5v supplies, and then use an Optoisolator to trigger off the Relay pin, that way it's isolated.
- Dump the relay board, buy an SSR. (Solid State Relay)
- Connect the wires to a breadboard then from the breadboard, link it to the solenoid, relay then place a 1000uf cap between VIN and GND, maybe even use an RF choke.
- Buy 2 cheap transceivers or use a Radio Link, to remotely trigger the relay
