I believe you need the table occurence name in the merge field, not just the field, e.g.:
Try inserting the merge fields again (or just use fields).
As fitch said you need to add the TO name into your merge fields.
One trick that can be very useful when you have limited space as will be the case for you once you have added the TO names is that the formatting for the merge fields is based on the format defined for the first "<".
This means that you can change the font size for the remaining part of the merge field:
Will show the merge field data at 14 point and bold even though the rest of the merge field is 8 point and not bold.
If needed you can input a custom text size of 1 point for the remaining characters in the merge field to ensure you have enough room to fit the fields inside the portal.
Thank you, Fitch! I know it is something very basic :-)
and thank you, Paul. That is a neat trick to get a better text layout.