Tablet to SimHub, one device won't connect.

Hi folks.

I've been trying to get SimHub Dashboards running on a chineesium tablet I've had lying around for ages.  It just wont connect, I've tried everything in the help pages and everything I can think of as well. (20 years network bloke, but retired)

I have a couple of iPads which connect to port 8888 and I get the dash display perfectly, but I don't have space to use an iPad!  

I'm not a big android person, but I can't see any differences between the network setup on either device, it just wont connect.  It'll ping fine, it's not blocked anywhere, it should connect fine.  As a secondary test Sim Dash works great, but I don't want to use Crewchief for this setup.

Any advice for odd tablets that aren't behaving?

Thanks.