Unzwar I can't sign up for a few months on Instagram accounts (except one, strangely) from my phone. I have a private account and one for drawings and only on the drawings I can log in. Other accounts I can't log in and create any new ones. If I want to log in there's "ERROR - Sorry, there was a problem with your request." But I can log on my laptop via browser on the account. I have tried many things: reboot my phone, reinstall instagram, reset my phone, but nothing works. I have an iPhone7, if that matters.
Hallo.ich I found the following link. Best read through it all, maybe you'll be five!
https://www.maismehl.at/update-zum-instagram-login-problem-leider-ist-bei-deiner-anfrage-ein-problem-aufgetreten/