The Teacher Retirement System of Texas is not an IRA. A Form 1099-R for a distribution from that system would not have that IRA/SEP/SIMPLE box marked, so it should not be marked on TurboTax's form.
If the Form 1099-R that you received has the IRA/SEP/SIMPLE box marked, it is a distribution from a traditional IRA, not from the Teacher Retirement System of Texas. If this form is from an IRA as indicated by the IRA/SEP/SIMPLE box being marked on the Form 1099-R provided by the payer, delete and reenter this Form 1099-R in TurboTax.
