To solve this issue, you can follow any of these two method.
Method-1:
You need to use the same channel in ExchangeApp and YouTube app. Your email could have multiple channels or you could use a YouTube app with different channels. In this case, this problem happens.
Just switch channels in your YouTube app and try again. it will work fine.
Method-2:
You can change the video player to an in-built video player to solve this issue. You can change the default video player from left menu > settings > Default video player then choose “In-built Player”.