Failure to connect over mobile data.

[jengleruk]

A slightly weird one here. 

When people ring my doorbell and I then answer on my iPhone 11 using the Arlo app:

- if my phone is connected to the internet over Wi-Fi it works fine 

- if connected over (strong) 4G I get no video or audio connection to the visitor. (Just a grey screen and a spinning wheel)

By way of testing:

If I connect my phone via hotspot to someone’s phone who is connected to the internet over mobile connection - it works ok on my phone 

if i connect that other person’s phone via hotspot to my phone connected to internet via mobile, it also works (on their phone, having installed the app and logged it in to my account). 

So this would rule out my data connection 

Any ideas? All settings for Arlo app in iOS settings are “allowed”.