I think everyone posted, replied under this thread (and many other stackoverflow threads) experienced the same issue. The issue seemed resolved for us just yesterday for a day, but today, it started acting up again, had to switch up wifi to log into Instagram. We also added email login after this incident.

thanks for the update, it started working yesterday for about 10 hours, then acting up randomly again.

Instagram has fixed the issue, at least it appears to be the case to us.

Are you sure about that? We're still getting this error.

at the time of my last writing, i was sure as all accounts are working fine. But today, it started acting up again. Now I had to change up to different wifi to login with Instagram.

should be fixed, check now.

Nice. I find this issue is resolved. All of our accounts are magically working.

We started having same issue since last Friday (Dec. 15, 2016) after working fine for months. Same user can login via oauth on one wifi, but not on the other, or even on mobile cellular network. And even when it worked on that wifi at one point, it does not work at other times. We have not found a workaround to fix this, reported to Instagram 24 hours ago, waiting...I tried to login to my account on instagram.com first, then go back to our site, browser would log in automatically. So far, we don't have a solution yet.

Update: as of now, All of our accounts are magically working. I did asked my facebook friends to pass the issue's urgency to Instagram team.

Just checked again, we're still seeing issues. I can reproduce, simply by using my personal account in a private window, it randomly fails in at least one of our environments (e.g. prod, staging, localhost).

It was working for us for the most of the day, but now acting up not working again...