Vivoactive 4s Heart rate sensor stops randomly

This has also just happened with my VA4s. I've also tried resetting with no luck. Less not flashing. Hr not being measured. It's very frustrating

It must think it's not in contact with your skin. Assuming it is worn tight enough, try cleaning it.

I've tried cleaning it with no luck. I've also checked the tightness when worn. 

I have tried to fit it looser or tighter and I’ve clean vA4s once or twice every day. No help

Previously I hade Va3 without these problems

I'm going to take it back to the store I bought it from tomorrow, its still under warranty. Its now having trouble connecting to my phone too. 

Seems that (todays) new sensor sw -update solved this problem

I have the same issue and it happened right out of the box - I’ve only had the watch for one day. How is this resolved?

Return it... There are other brands where you dont have to wish for basic functionality. This IS a bad value product.  Keep searching ;)