Make sure you’ve sent the machine configuration per the assembly instructions for your machine — for 517 and later: Setting Grbl Configuration in CM 517 and later
Note that it may help to temporarily disable or disconnect accessories when troubleshooting. For configuring a BitSetter see: Introducing BitSetter - Automated Tool Length Probing for Shapeoko - YouTube
There is a basic page on troubleshooting the homing switches at: Home Switch Troubleshooting - Carbide 3D
There is also a Carbide 3D Answer video: Basic Shapeoko Limit Switch Troubleshooting - YouTube
For the new inductive homing switches: Troubleshooting: Proximity Switch Troubleshooting - YouTube and Adjusting: Adjusting the Proximity Switches - YouTube
If you continue to have difficulties, let us know at support@carbide3d.com (let us know you’ve seen the above links and what you’ve tried and let us know step-by-step what the machine does) and we’ll do our best to get this sorted out w/ you.