In addition to
JavierP reply: Report what kind of Phone is that. If it's a Samsung
Gs7 the setting
of AutoRotate is Not shown on Settings-Display: Inadvertently 2-days ago that option
it turned off on my SGs7 expend about 1hr. Trying to fix this and give up
Tried again and swipe finger from TopScreen to bottom. Call Me the attention the 4th icon-Showed
a Phone with a lock it says portrait. I tap on it and Bingo it switched to an AutoRotate icon.
I opened Contacts app & turn my Phone on and was able to View text in landscape
position. This option it use to be in "Display" but changed in SGs7 - Stay Tuned!