Nest thermostat starts heating but soon switches off again

[waribai]

Hi, My nest is turning the gas heating on but after a few seconds it cuts out again. I had this problem before and cancelling the schedule and restarting without wifi connected on the phone apps worked. But this time it doesn’t seem to help.

[Patrick_Caezza]

@waribai 

How is the Nest wired?

Does it have a C wire installed?

[waribai]

Yes. I believe so. It was installed over a year ago by a plumber and electrician