Watched 1 video during happy hour, got 1 gem, now no other videos will play
Do SP this on purpose? It wouldn't surprise me.
On all other games, video rewards are simple and ALWAYS work as intended. On ML, there is always some new devilry that seems to cheat players out of their free gifts.
I wonder if you are having these issues due to your region....personally I do not have any issues on google play version, amazon android version or when using memu emulator. Also your settings may be affecting it as well, on my google version i turned off the option for ads based on my personal preferences. And of course I clean my cache weekly.