For my last 2 or 3 arena runs I have only got 2 loses and then the chest for completing your arena run ended. This happened 3 weeks ago and now agian. BigPappi #11833 (North America)
Have a look at the Common Issues sticky thread:
Here are some of the commonly reported issues that can be resolved.
Unable to use specific cards in Adventure Missions
Certain card effects are disabled while in Adventure Missions. This is to prevent them from trivializing all of the encounters. Some examples include:
Mindbreaker
Sideshow Spelleater
Grizzled Wizard
Golden Cards are not animating on mobile?
After installing the Hearthstone app, mobile devices will need to download additional files which contains extra sounds and animatio…
Especially the second to last section, linking to this:https://us.battle.net/support/en/article/17276