This error message may be caused by merge fields in your Word document that need to be re-merged. When clicking on the merge fields in the word document you may notice that they no longer highlight gray and may behave like regular text. To resolve this issue try re-merging the word file with your Altru header file and re-uploading the letter

Download the CSV header file
1. Click Marketing and Communications > Export definitions 
2. In the Membership renewal section click the drop down arrow next to the export definition that your letter uses > Click generate Header file
3. Save that file to your computer

Perform a mail merge
1. Follow these steps
Re-upload the letter back to Altru
1. In Altru click Marketing and Communications > Letters
2. View Letters > click Update Template
3. Click the green arrow to upload the file that you just created from your computer
4. Click save