Despite Microsoft’s best efforts, it appears the company has not succeeded in heading off an EU investigation into its bundling of Teams.

Microsoft has been working to address EU concerns over its bundling of Teams with Office following a complaint by Slack that Microsoft’s practices gave it an unfair advantage. The company has made major concessions, including unbundling the app and even being willing to charge for it.

According to Bloomberg, these efforts do not appear to have been successful, with the bloc reportedly moving forward with a formal complaint. The EU Commission is reportedly preparing a list of objections to send to Microsoft in the coming months.