I found a suggestion online and it worked. I thought I had done it yesterday but I hadn't actually completed the process.

This is what worked for me:

In Windows Search I looked for Microsoft XP Writer; if you don't see it, you can add it to the list. Check the box and click ok. Restart your computer.

I just added the feature yesterday but didn't enable it. I did it just now, rebooted, and emailed the invoice successfully.

I hope it works for you too!