Streaming not working

Hi I recently changed my home network in a couple of ways:

1. Changed providor to slingshot

2. Switched the main router from an Asus model to a Fritz 7490. Main reason was so I could use the Asus router as an access point to improve wifi coverage. The Asus has better wifi than the fritz.

I also have another fritz 7390 as a access point, not sure if it has any affect but just staying it for info.

So since this change I'm finding I can't stream tvnz or three live tv on my phone anymore using their apps.

Series works fine but takes a little while to get started ed, it only seems to impact live tv.

Spotify takes a minute to start but then works fine ( use to start straight away) Youtube is fine.

The network is a gigabit network and all connections are reporting as connected at 1000mb/s.

The fritz doesn't have any QOS setting, so I'm a bit stuck on what could be causing this issue. Any suggestions?