Can't re-install Pokemon Go

Solution 1:

As Jerry commented on the question:

Niantic has troubleshooting guides for both Android and iOS.

Common checklist:

  1. Try cleaning the app data and log in
  2. Do clean uninstall (quit app, clear data, uninstall)
  3. Reboot phone
  4. Reinstall
  5. Sometimes it's a server side thing and you have to wait