I have interest income from a foreign bank account. Turbotax is flagging the 1099-INT entry for the Payer's Federal ID/ TIN no. What should I enter in it?

Turbo Tax generally does not ask for the payer's ID/TIN number unless this was imported.  if this is the case, delete the 1099 INT entry and report it again. This time, you won't be asked what the Federal ID/ TIN is.