The IRS is rejecting a return that has correct information submitted. Every suggestion from TurboTax doesn't work. Can't speak to live person. How can this be fixed?

If the IRS is rejecting the tax return and everything on the tax return is correct then you will have to print and mail the tax return.

See this TurboTax support FAQ for printing a tax return for mailing using the online editions - https://ttlc.intuit.com/community/printing/help/how-do-i-print-and-mail-my-return-in-turbotax-online/01/26258

See this TurboTax support FAQ on how to contact Support - https://ttlc.intuit.com/questions/3401489

Or -

Use this website to contact TurboTax support during business hours - https://support.turbotax.intuit.com/contact/
Support can also be reached by messaging them on these pages https://www.facebook.com/turbotax/ and https://twitter.com/TeamTurboTax

Father-in-law passed away in December.

When someone who has passed away is listed on a tax return, it is not uncommon for that tax return to not be able to be e-filed. If those handling the final arrangements have done their job (usually the funeral home) then the social security administration was notified of their passing. The IRS pulls taxpayer information from the social security system every year. When a tax filer (or dependent) is marked as "passed" then the IRS permanently locks their SSN so that it can not be used fraudulently. Most likely this is your case. Therefore you have no choice but to print, sign and mail the tax return to the IRS.

DO NOT under any circumstances send anything with the mailed return until and unless the IRS specifically request it. In your case they may (or may not) request a birth certificate and/or a death certificate. But do not send those items unless specifically requested by the IRS.