Is your VFD throwing a Fuse Open fault code? Here's what to do next. 

Check your fuse, is it normal?  If the fuse does not look normal then change the fuse and perform a checkup on the IGBT.  

Next, check the limit switch or fuse show signs of any abnormalities? If you find abnormalities replace the limit switch or fuse wiring with a new one. If it looks normal then change the control PCB just to be safe.