VS403181: The number of tag names in the organization has exceeded the limit of 150000
Issue: VS403181: The number of tag names in the organization has exceeded the limit of 150000.You can reuse existing tag name or delete unused tag names
Solution: Azure DevOps has a limit of 150000 tags per organization and as the error states you might have reached 150000 tags by somehow. So you may need to delete the tags which are not in use or reuse the existing ones and that’s the only solution.
This issue might have been also caused by tags created by API calls which might have created 1000’s of tags like these.