HELP. NO SPOTIFY CONNECTION in djay pro w/ ipad when on cell/LTE

NO SPOTIFY CONNECTION WITH Djay pro for ipad over cell/LTE connection! Wifi works but cell should too! But it doesn’t. Yes, i have the data on cell option enabled in my ipad settings. Still! I need spotify with djay pro for ipad to work on the go. I don’t always can rely on a wifi connection where iam booked. I use djay pro on my 12.9 ipad 1st generation with ios 11. Who is experiencing the same issue? Who has a fix for this?
Best, Sid