My husband and I filed an ameded return last year and changed our status to married filing seperately. where do I find his tax liability? It only shows mine?

Enter the 2018 from the original 2018 tax return that was filed.  If you filed as Married Filing Jointly then the 2018 AGI is the same for the both of you.

If your tax return continues to be rejected with the 2018 AGI then enter a 0 (zero) for the AGI and e-file again.

If this is also rejected then you will have to print and mail the tax return.

See this TurboTax support FAQ for printing a tax return for mailing - https://ttlc.intuit.com/community/printing/help/how-do-i-print-and-mail-my-return-in-turbotax-online...