I owe federal $1589. On line 11a, it ask me to enter the amount I can pay monthly. When I enter my amount if keeps giving a error. Can you help me with this?

[DoninGA]

Make sure that you enter a whole dollar amount, no cents.  The amount should be at least $23 or more with a tax debt of $1589.

[Critter-3]

Back up and just choose to "mail in a check" since the payment plan is not set up in the TT system ... you must do it online at  https://www.irs.gov/payments/online-payment-agreement-application