Nokia6 is Not compatible with Vodafone 4G
I am from Pune,India.
I checked same SIM with different device(Same location) and its working fine.
I contacted to customer care of service provider, they also replied that Nokia handset is not compatible with Vodafone 4G.
It's working no doubt.
But did you checked 4G speed?
For me also it's working, but with Nokia 6 speed is around 1mbps and with other device it's around 9mbps.
Oh, Then it may be a individual device problem.