When logging into an OU login page like One.ou.edu or a Microsoft 365 site, if only an OU username is entered, it may say that the account doesn't exist. The login page will then sometimes ask if it is a work/school account, or a personal account. If work/school account is selected, this error may show up: "AADSTS90019: No tenant-identifying information found in either the request or implied by any provided credentials."
To resolve this issue, please return to the main login page for the site and type in your full OU email address, rather than just your OU username.