What does: "x-pmta;all sources disabled" mean?


Can anyone help me what this bounce message means?

x-pmta;all sources disabled

I get it on almost all yahoo emails now, started a couple of days ago. Hard bounces

Can't seem to find any info for this anywhere and would appreciate all help
I don't know what details? There is nothing in application log, there is just bounced emails showing this message
all hard bounces
most yahoo, some aol

I did not change any settings or anything, I am at a loss what's happening.
Only thing I know is I got about 10k new emails in blacklist over nicht, all hard bounces with this error message