I have a second account which when I opened I linked to my main with a multi account login - therefore it never asked me to set a password. I then removed it from the multi account login system, and it never asked me to set a new password. The other day I accidentally logged out of the account and I can't get back in! It never asked me to set a password, so wtf do I do? It doesn't accept the same password as my main. PLEASE ADVISE I'M DESPERATE!
System Configuration: Windows / Chrome 86.0.4240.75
Try going to Instagram's recovery page. Enter the phone number, email address or username associated with that account and click Send Login Link. This will help you to set a password, so that you can access your account.