Acrobat won’t load on my iOS devices

I'm a heavy user of acrobat reader. 

opening a new file this morning, the app opened momentarily, the closed before opening the file. 

I offloaded and reinstalled the app ... then deleted and reinstalled the app. Same result. Acrobat starts to open, then closes before opening a file or showing 'Home'.

my iOS is up to date. 

same problem on my iPhone and iPad. 

???