SecureGo gives notice about my phone being jailbreaked - but it isnt

My bootloader was unlocked, so I tried to lock it via adb and now Im in big trouble: I cant access my custom ROM or TWRP, all my phone is doing is showing the fastboot mode. Via the command adb devices there is just an empty line, no device is shown. Before I worked via the command line and it all went smoothly until I executed fastboot flashing lock. Can you tell me what I can do?