Good day, If I want to open an MSG file comes an error message indicates that no matching app is available. But the Outlook app is installed! If I install a simple MSG viewer will open the email!  What is the problem?

Unfortunately this is a limitation of Android not Colligo. Android does not natively handle .msg files. Colligo does not contain any inherent viewers for .msgs, and it seems that Outlook for Android has not developed a handler either. A third party application would be required.