Interface connection failed

[SPN]

After having tuned dozens of vehicles, suddenly I get the error message "no interface connection". I tested the OBDII port for power and tested the cord to interface unit for continuity--both were OK. Then I tried to read 2 other cars that I had tuned previously and I get the same error message. What has happened? I would appreciate any help as I have 2 vehicles waiting to complete.

[planethax]

Try a new USB Cable.

[SPN]

Thanks planethax! Always be to remember the basics.