I too got the 4464c. As answered already. Normally means w-2s orn1099, WAGES in general. Example. I made a typo on my current 2019/2020 filing, I was off by one...

I thought I took a picture of the W-2 and uploaded it to TurboTax but after me auditing myself for about 6 hours I put box number two or box number for goes and...