I tried rebooting my phone. Removing and reinstalling Instagram. I found info on the web that says it's a bug. I tried logging in with my username and password. I tried logging in using the Facebook log in option.Whatever I tried, the problem persisted.
Until now. Maybe it's just coincidence, but this is what I did.
- Launch Instagram and log in, if necessary.
- Press on your profile thumbnail at the bottom right.
- Press on the gear at the top right.
- Scroll all the way to the bottom.
- Choose the option to Log Out.
- When prompted to remember your log in, choose Not Now.
- Confirm by pressing on the Log Out option.
- Log in again.
- Log out again, but this time choose "Remember".
- Log back in.
If this worked for you, please let me know in the comments below, and feel free to share the solution with others.