Server: Bedrock Dedicated Server for Ubuntu 1.19.21
Clients: Xbox One, Xbox One S, and PC - all updated to latest available versions.
Problem: When a resource pack needs to be downloaded the clients hang.

When joining the normal prompt appears telling me a resource pack is needed and it is 1MB in size (which is correct). If I click Download and Join, it says downloading packs 0 of 0 and does nothing - it just sits there forever. 

If I ignore it and just click Join, the server works correctly but obviously the resource pack is missing. 

No error messages on the server.
No error message on the clients (PC or Xbox). Just nothing happens. In previous versions the small 1MB resource pack would download in seconds and the game would launch.

I have checked:

• UUID's and Version # in manifest.json + world_resource_packs.json,
• checked file placement compared to previous 1.17.40 install
• tested the resource pack on Minecraft for Windows (and it's the same as I previously used on 1.117.40)
• tested server on multiple worlds
• restarted the linux server many times
• restarted network router