When I convert a DWG to a PDF, I sometimes get an error message "YOU DO NOT HAVE A PDF VIEWER INSTALLED" (See image below). I DO have a viewer installed because this only happens sometimes on the same DWG file. When this happens, I save and close the drawing, open it up again and then it will sometimes work fine, but not always. Very strange that the drawing gets converted to a PDF correctly sometimes and other times I get an error. Any thoughts???
Notes:
I use Adobe Acrobat Reader DC as my Viewer and this is set to default
I am using AutoCAD 2021LT