Synology VPN Plus Android Client Will Not Connect Over EE 4G

[scotttoward]

I have a Pixel 2XL Android 11 phone 
I have Synology VPN Plus client installed 

When I connect to my Synology VPN server over WIFI from an external location it works fine
When I connect to my Synology VPN server over EE 4G I get connection timeout 

This used to work just fine earlier this year but now it does not 

The weird thing is I can connect my laptop to a 4G hotspot on the same phone then use the Synology VPN client on my laptop to connect to the VPN just fine  

I have tried changing the server ports of my VPN server from 42500 to 443 no difference

I tried the same phone with a different Vodafone sim and it works fine so must be an issue with my phone and the EE network 

[mikeliuk]

Hi @scotttoward ,

Add a new APN duplicating most things except the name of the settings and that IPV4V6 line.

[scotttoward]

Thank you so much that worked 

Created the new APN profile as directed

https://apninternet.com/ee-united-kingdom-apn-settings/

Key changes 

Internet (New)

APN Protocol is IPv4

APN Roaming Protocol IPV4

[mikeliuk]

Hi @scotttoward ,

Super! I recommend that you report that issue to the developers so they can locate the root cause and provide advice for other users who hit the same issue. Most likely they are using IPv4 literals in their implementation so they may not be compatible with IPv6 or IPV4V6 dual-stack.

IPv4 is not likely to go away for a long time but it would be good to revert that work-around before too many years go by.