Thanks for your post and welcome to the community.
I would request you to please once install and uninstall the app and request you to please try login in to your PayPal account.
If you are still facing issues, then this issue could happen for various reasons. I will help you with some basic workarounds which might help you to resolve the issue.
1) Please use a different browser
2) Please clear the cache, cookies and browsing history of your internet browser
3) Please try in computer if you tried before in mobile and mobile browser, then try.
To learn more on to fix login issues, please click here and hope this information helps.