Ipad air 2 keeps on pausing on youtube, dailymotion, spotify. Why?

Have you tried any of the standard fixes.

Have you tried a hard reset of your iPad by holding down both the Home and sleep/wake buttons simultaneously until your iPad goes to black and restarts with Apple logo, then release the buttons?

In Settings App, General, Reset, Reset All Settings?

In Settings app, General, TURN OFF Background App Refresh?

Do you run your iPad Air 2 with scads and scads of background apps still running in the background?

Quit apps to reduce the amount of background running apps!

Do you have scads and scads of active website tabs running in the Web browser?

You need to reduce the amount of active website tabs running active in the Web browser!

Yeah!

Those are probably your BEEG issues!

No one needs scads and scads of apps and website tabs actively open!

All of that eats up into the iPad's hardware resources and eats up battery life faster.

Your iPad Air 2 ONLY has 2 GBs of RAM!

Stop loading up your iPad with excessive amounts of background apps and excessive amounts of active websites in web browser tabs!

20 tabs is not what I call excessive, but it’s enough to probably cause issues.

If you have more, then say, 20-30 apps open in the background, depending on the apps that are open, that is kinda excessive, too!

That is probably your EXACT problem!

Turning OFF Background App Refresh would help to some extent, too!

I am giving you advice and POSSIBLE solutions.

If you do not try these, you won't solve your video streaming issues and you’ll never know for sure, right?

It may solve your issue. May not.

The only way to test a hypothesis is try it!

If this works for you, great!

If not, then there could be another issue at work.

Good Luck to You!