I have a critical diagnostic ref # 58843 stating that I can only file a 4898 on due date. I already had filed the 4898 and now I cannot file the tax return.

Screen 9. Remove the 1 in the first entry. You can complete the next 4 entries so the 4868 will print with the return, but you don't want that first entry. 

I think that will fix your situation.

P.S. My lovely daughter is Brenda, but to me she is #1. 🤗

I think this is a bad diagnostic.  It only appears after the last Lacerte update, and never appeared in prior years.  The 1 on the first line is automatically populated when you do the batch efile of extensions, plus you WANT it to be there or else the invoice does not pick up charging for the extension prep.

Nonetheless, I think it is only a diagnostic for the efiling of the extension, not for the return itself.  Double check your ack file that the extension was accepted.  Then the filing of the return is a separate filing as the IRS already knows you have the extension so you are not refiling for it.  I would transmit even with the "critical" diagnostic, and hopefully someone at Lacerte is working on cleaning this up.