One specific app on my Apple iPad will not rotate orientation! Only the one!

My Apple 9th Generation iPad works beautifully. No rotation problems. But only one app, the My Spectrum App will not rotate and It now stays in portrait orientation. It used be in landscape when I first downloaded it from the App Store, but just recently switched to portrait and it will not rotate. My screen lock is not on. Has any one else had this specific problem? Perhaps it is not an iPad problem, but something to do with the My Spectrum App? Would appreciate any information. TIA