pymysql.err.DataError: (1406, "Data too long for column 'letter' at row 4")

Hello, I’m working to customize my quotation form, and I add a new section with a link to the Terms and Conditions and also a text editor to get the data from the select term.
I’m sure that i made everything well but I get a strange error that says that the Data too long for column ‘letter’ at row 4

as you can see below

I can’t retrieve the terms to the text editor now

The use the link Type is documented here:

Might it be necessary to add a Doctype in the Default box?