Samsung galaxy s10. Won't load on mobile data but loads on wifi

Hey, SuperTan! This sounds very similar to the T-mobile/Sprint issue with IPv6 connections. Checking here, it looks like the post was made through the mobile data connection and its IPv6.

This isn’t officially supported by Blizzard, but changing the APN to support both Ipv4 and Ipv6 or switching from LTE to CDMA should help with the issue. Here’s our known post on the issue:

The reason why this happens is because Hearthstone only officially recognizes IPv4 currently, and these issues is something that our team is working on addressing individually with each carrier. There’s no estimated time on when our team will be able to address all issues at the moment, but they are working on it. In the mean time, hopefully some of this information will help find a more permanent workaround than using the home wireless connection.