Amended 2024 return unable to efile

I have attempted several times to efile my amended return for 2024 after discovering an error on my original return.  It goes through all the way to the end, saying "success", then a message pops up saying 

"Your transmission didn't go through

We could not e-file your return for the following reason:
Tax Year 2024 transmissions are not available."
 
Tried over several day with no success to date.