Hi Guillermo.

Can you inform us what version of Powerbuilder you are using?

Andreas.

The version of Power Builder 2019 R3  /  La version de Power Builder 2019 R3 

Microsoft® Outlook® para Microsoft 365 MSO (versión 2211 compilación 16.0.15831.20098) de 64 bits

thanks

Are you aware of the following note in documentation:

64-bit PowerBuilder mail applications can only work with 64-bit Windows MAPI. 32-bit PowerBuilder applications can only work with 32-bit Windows MAPI.

Building a Mail-Enabled Application - - Application Techniques (appeon.com)

Andreas.