Q: Unable to login to "App and iTunes Stores" in iOS

Let me preface by describing how the problem came to be. Randomly I was no longer able to download apps from the App Store. I would press the "Get" button followed by "Install" and the button would then go back to "Get" again. It does this for any and all apps in the App Store. There is some kind of error message that pops up after hitting "Install" but vanishes instantly so I have been unable to view it.

When attempting to find a solution for this problem, one of the suggestions was to sign out of the App Store in the "App and iTunes Stores" section of the Settings app on my iPhone 6s. I followed this advice (only the App Store and not the iCloud section) and now there is a "Sign In" button in the "App and iTunes Stores" section instead of my Apple ID. This brings me to my current issue.

I am unable to sign in to the App Store by any means. When I click the "Sign In" button inside of the App Store section of Settings, the window pops up with my email address already filled in to the email field and then I type my Apple password and continue my attempt to sign in. The window then closes with no errors of any kind and brings me right back to the "App and iTunes Stores" section where it still says "Sign In". I have verified Im using the correct credentials as I have changed my password multiple times just to make sure.

I have also attempted to sign in via the footer of the App Store itself. When I open the "App Store" app and scroll all the way to the bottom, I am presented with a "Sign In" button here as well. When i click this button, a window pops open with the sign in options and vanishes in a second. I am unable to click any options from there.

Sone please help me to resolve this problem without having to resort to a restore as that is not an option for me.