The problem stems from what appear to be several errors you have made on your tax return.
"In TTax it is entered under "Tax withholding that you haven't entered yet""
As baldietax said, estimated tax payments are not tax withholding. They must be entered as estimated tax payments, not tax withholding. TurboTax has a separate page for that.
"The mutual fund company did not give me any tax forms for these transactions."
Also as baldietax said, the company is required to issue a Form 1099-R for any Roth conversions. If you received no such forms, you'll need to investigate that with the company. If the conversions made in 2024 were not reported to you or the IRS on one or more Forms 1099-R, the IRS will not be aware of this taxable income and will reject the payment of any the taxes for taxable income that is not present on your tax return. If the company did issue a Form 1099-R, the IRS should have received it from the company, would have detected the underreporting of income on your tax return, and likely would not repeatedly return the estimated tax payment.
baldietax also addressed the issue that, unlike the default treatment for tax withholding, estimated tax payments are credited when actually paid. Because, by default, income is treated as received evenly throughout the year, if your Roth conversions and estimated tax payments were made late in the year and you do not qualify for one of the safe harbors, you'll likely need to annualize income on Schedule AI of Form 2210 to avoid underpayment penalties for earlier tax quarters.
