I currently have several flows that send automated emails based on fields in a SharePoint List that are currently using the SendGrid connector. I used this connector because I was unable to connect to the Office365 Outlook connector within Power Automate with a service account. I have been informed that we will be decommissioning the SendGrid connector and I must use the Office365 Outlook connector. I have no issue connecting my company email to the connector but I need to connect a service account with the same domain so that the emails will send through that account and not mine and I am getting the error below when attempting to sign into the connector with my service account.

My IT department has been unable to point me in the correct direction to get this rectified. Has anyone encountered this type of issue? I am assuming that something needs to be adjusted within the settings of the service account but without specifics my IT department has been unable to assist. My initial research seems to keep coming back to activating the service account on Outlook 365 or Microsoft 365. I am not sure if its the same issue but I am also unable to connect this service account to the new Outlook.
Any assistance with finding out what is needed to get this to work would be greatly appreciated.