Two beeps a delay then fail light flashes with beeps

One of your black handle switches is shorted. Check which side the fail light is flashing on to tell which switch is shorted. If the light is flashing on the front, the front black handle switch is the problem. If the light is in the back, it is the back switch. Instructions for replacing the switch can be found here: https://intellistitch.zendesk.com/entries/22665348-i-s-switch-replacement-procedure