Employee Max Roth Solo contribution

I am using Turbotax Home & Business version I purchased. I am a self-employed independent contractor.  I know I can contribute $19,500 to Roth Solo employee contribution + $6,500 catch up contribution.  I plan to send contribution after filing taxes, but before April 15, 2022.   When I enter these figures + employer contribution of $38,500 (as I am my own employer) under page Individual and Roth 401(k) Plans, my current Federal Refund amount flips into a "Taxes Owed".    Why is this happening?  What am I doing wrong?  Should I not enter any amount on this page, and get the refund and then send the amounts in to my investment financial institute?   Need help please.