Son had no income in Colorado in 2023. According to the state website he should qualify for the sales tax refund, turbotax says he isn't eligible. Any ideas on how to help him receive the refund

Does your son meet all of the qualifications?  The Colorado State Sales Tax Refund Credit is allowed only to individuals who were domiciled in Colorado for the entire year. Other requirements may be found here.

In TurboTax Online, access the credit at the screen Qualifying for the Colorado state sales tax refund.

Learn more states:

If you are a full-year Colorado resident who was under 18 as of January 1, 2023, you may claim the state sales tax refund only if you have a Colorado tax liability (Form 104, line 13  must be greater than 0) or you are claiming a refund of Colorado wage withholding on a W-2. Your return must be postmarked by October 15, 2024.

Part-year resident and nonresident individuals are not eligible for the state sales tax refund.

Individuals incarcerated in the Department of Corrections, incarcerated in a county or municipal jail, and certain individuals committed to the Department of Human Services for at  least 180 days in 2022 are not eligible for the state sales tax refund.