Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Based on the message shown, this does not necessarily appear to be a conflict between a personal Microsoft account and a business account. Instead, the account currently signed in does not have the required permission to access or manage the subscription in the Microsoft 365 Admin Center.
When the Microsoft 365 free trial was created, do you recall which account was assigned the Global Administrator role? A separate administrator account may have been created during the registration process, possibly with an address ending in .onmicrosoft.com.
Please check the original Microsoft 365 welcome or trial confirmation email, as the administrator username may be listed there. If another person set up the trial, you may also need to ask that person or your organization’s IT administrator which account has the Global Administrator role.
Once you identify the correct administrator account, select Sign out & switch on the displayed page, and then sign in with that account.
Please feel free to take your time checking this information and reply with an update when convenient.