Dear Ulises Olivares,
Good day! Thank you for posting to Microsoft Community. We are happy to assist you.
Based on your description, you're experiencing issues with downloading files in the new Outlook for Windows.
1. If you revert the Outlook to the classic version, does the issue happen?
2. Would you plase check the issue with another device and let me know the result.
3. Are there any other user has the issue in your organization? When did the issue happen?
4. Would you please send me some screenshots about the downlaoding process and the error message? Then I can do some test accordingly.
Please understand that our initial response may not always resolve the issue immediately. However, with your help and more detailed information, we can work together to find a solution.
I look forward to your next update for further analysis. Thank you very much for your cooperation.
Thanks for your precious time. Have a nice day.
Sincerely,
Sherry | Microsoft Community Moderator