Issues with connecting to masts with only band 20?

[JTScotland]

Our local mast only has Band 20/800mhz so only provides access to 4G and needs phones that have 4G calling (and only contract sims not PAYG sims)

Has anyone had issues with Sony Xperia XZ2 compacts connecting to these masts?

In this case it’s an ee-only mast so no other networks available on it and no other masts available in the area

His sim works in my iPhone 8 but his sim doesn’t work in his Sony phone
His phone works ok when he’s 20 miles away and connecting to masts that have multiple 4G bands
He’s set his phone to only use the ee network, 4G as a preference and we’ve checked APN settings, changed tariffs (it resolved a problem for me and a neighbour) and ee have replaced his sim

We’ve been speaking with ee for several hours but they’ve run out of ideas

Any ideas?

 

[GavinAshford]

Is the XZ2 Compact a factory unlocked model, or one provided by another network (and subsequently unlocked for use with EE)? Is it using the latest available software update for it?

To me it sounds like EE haven't 'approved' the XZ2 Compact for VoLTE use and as such can't get access to B20. Or, if they have approved that model, perhaps it's using old software, or software from another provider, that is blocking its use on B20.

Edit: EE themselves don't list the XZ2 Compact as VoLTE compatible. They do list the XZ1 Compact and non-compact XZ2.

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ee.co.uk

Just feels a bit unlucky the XZ2 Compact isn't approved.

 

[kommando828]

Three have issues with some phones on band 20, they only guarantee support of the phone is supplied by them and is on their list as being compatible.