Amended return stuck in a "transmission trouble" loop

I tried submitting an amended 2024 return this week. Near the end, I got a confusing message:

 

"Returns other than CA must be mailed." (I'm a CA resident.)

 

I took this to mean that I could not file amended return with the IRS electronically. But on the subsequent steps, it let me choose e-file for my federal. Just after I hit Submit, it said I needed to update the app. (I'm using Deluxe for Mac.) So I did that. When I resubmitted, it DID accept my CA form...but my federal form status is ambiguous:

 

"Transmission trouble – please try again."

 

So I've tried repeating those steps. But every time I go through the File steps again, it shows only my CA form (accepted), and lands me back at the same e-file status ("Transmission trouble") for my federal form.

 

Do I have to print out my 1040-X and mail it to the IRS? I'm only nervous because I put in my payment into for the IRS, and I don't want to pay them twice. Thanks.