Update your Office for Mac 2019 to Office for Mac 2021
As Office 2019 for Mac has not received any quality and security updates since 10.10.2023, a switch to Office 2021 for Mac is mandatory.
You can order Office 2021 for Mac directly from the service portal: Microsoft Campus License
IMPORTANT: Do not connect to an M365 account, otherwise an update to M365 will take place and can only be used with M365.