Mortgage Lender tells me to not pay full credit card balance?

[Eric Lind]

I recently filled out pre-approval application for a mortgage, however, the lender did a hard pull and told me they came back with no score. Credit karma gave me a score of 711, I know it is an estimate but I found it weird one had a score yet the lender got none. The lender told me they got no score because I was paying my credit card balance to zero. They told me to get a Capital One secured card and never pay it to zero. I could not find any affiliation between the lender and Capital One. Is leaving a $10 balance at all times a real thing or a possible reason the lender did not pull any score? I feel like I am being lied to or manipulated for being young. Everything I know and have read and learned says to pay off credit cards on time and to zero since that is the point of credit and how you show you are financially responsible. Any advice is very appreciated!