Why does my iPhone app Acrobat Pro/Adobe Reader stop letting me send PDF to Outlook?

I'm just about fed up with Adobe. I frickin loved this thing, had NO PROBLEMS up until about a month or two ago when it started malfunctioning on my iPhone. Works perfectly fine on my desktop. One day I was on my phone and I randomly got booted out of my Adobe app. Made me sign back in... which was weird. Signed back in and then it would no longer allow me to open PDF files then attach them to an Outlook email, which it used to ALWAYS allow me to do. The only way around it is to delete the Outlook app and reinstall it once or twice a week - then it will work properly again for a few days, until I have to reinstall outlook again. It's getting very old. Can't get ANY help from Adobe customer service, as they don't have a customer service phone# for my app... very frustrating. I've tried the online rep chats and each time, they tell me that I don't have the "pro" account basically, so I need to spend more money and upgrade in order to send PDFs over my phone, then they disconnect and send me to sales. If that's the case, why have I been able to do this the whole time? For years, with no problems... No error page pops up or anything, when I click "Share To" all of my app options pop up, I click the Outlook icon and it just keeps loading, doesn't do anything. All of my apps are fully up to date so I have no idea what the problem is but I am so very frustrated. Yes, I've tried deleting and reinstalling my Adobe app, which doesn't help. Only helpful thing is deleting my outlook app and reinstalling it - but as mentioned, this only holds up for a few days, then it acts up again. Please help!