Can't log in to Instagram

Hi everybody!

I have such an interesting problem: one day suddenly I was logged out from business instagram account and till now for 5 days I can't log in to it. I'v tried to reinstall the app and logged out of my own personal account. So, now I can't log in to my personal and business accounts on Instagram. I've texted to Fb support, cause Instagram doesn't allow you do it (there is no support if you can't login and you have no possibility to text about it at all), but they said that the problem is with my devise. Then I removed all settings and information from my iPhone 8 plus and install the app - It works, I can log in to my personal and working accounts. But when I restore my iPhone with the latest backup - same problem, error while logging into IG. Here is my question: Can I remove part of information? Just settings and all the data of Instagram? Or what can I do not to loose all my data but refresh my IG and work? 

Thanx!