Issue When trying to create Job Opportunity and Correspondence - error message was popping - "This message is for C/AL programmers: The call to member SaveAs failed:  Incompatible file type and file extension.
Check the Save as type in Word - File - Options - Save - Save files in this format - Change .docx if its .doc. 

If using Microsoft Access  Object Library version is greater or equal to 12 then, system is using .docx extension else using .doc.