Please see below for Alternate Solution:
I. Upload Excel File in File Cabinet
a. Navigate to Documents > Files > File Cabinet
b. Choose a folder
c. Add file
II. Get the system generated URL for the uploaded file
a. Edit the uploaded excel file
b. Copy the secure URL provided (https://)
c. Make sure Available Without Login is marked
III. Create the Email Template
a. Navigate to Documents > Templates > Email Templates > New
b. Choose Text Editor
c. Click Source (indicated with the button DIV </>)
d. Add the codes <a href="(paste copied URL in step 2 here)"> Click Here </a>
With the provided Alternate Solution, users can now send excel file only that it is not attached but is linked within the html that we have added from the message field.
To confirm if the Alternate Solution is working, users can do a test mail merge and see if by clicking the words "Click here" will automatically give them the option to open or save the excel file.