If there are conflicting licenses on your machine, you can run the Office License Removal Tool to clear old data and sign in fresh.
This is the only recommended and safe method for individual users. Everything else is a variation of an "activator" with significant downsides.
Split the cost among up to six users for a significantly lower price per person. Microsoft Office 365 Activator For Mac
Bypassing a software license might seem like a victimless crime, but the secondary consequences to your Mac are highly destructive. 1. Malware and Ransomware Infections
This public link is valid for 7 days and shares a thread, including any personal information you added. This link or copies made by others cannot be deleted. If you share with third parties, their policies apply. Can’t copy the link right now. Try again later. If there are conflicting licenses on your machine,
: For organizations, the Volume License Serializer is the official tool used to activate multiple Mac devices under a single business agreement. Troubleshooting Activation Issues
Legitimate Office 365 applications receive weekly security patches and feature updates from Microsoft. Pirated software cuts off your connection to Microsoft’s official servers. This leaves your applications buggy, prone to crashing, and vulnerable to newly discovered security exploits. Split the cost among up to six users
Tools that modify local files are broken by automatic software updates.
Unofficial activation often breaks the ability to receive patches, leaving your Mac vulnerable to security threats.