Based on information provided,visa is not immediately available for yourprioritydate

[senthu]

I am an EB1C applicant. I got the rejection notice in my mail today.

My priority date was Jan 21, 2020.

I applied for my GC in DEC 2020, when the DATES FOR FILING OF EMPLOYMENT-BASED VISA APPLICATIONS was 01NOV20 , the FINAL action date in that bulletin was "01APR19".
The application was mailed on Dec 15th 2020, and received date is 16, Jan 2021

I am totally confused why my application was rejected citing this reason. Is this a clerical mistake, could this be coz mine was a concurrent filing 485,765,I131 together and they were considering the Final Action Date instead of the date for filing?

[Enub4]

To see which of the 2 calendars you need to use to apply for AOS (send I485) you need to visit https://www.immihelp.com/all-visa-bulletins/

For December 2020 USCIS said to use Dates for Filing and for India the date is 01NOV20
For January 2021 USCIS said to use Final Action Date and for India the date is 01SEP19

If you ask me, this is an error on USCIS part but in the end almost all errors that they make we need to pay for their mistakes. You may try to appeal citing that you send the package in December and the Dates for Filing were in effect and they should accept your package.

The "good" news is that your category for March, using the Final Action Date is 01AUG20, because your priority date is 21JAN20 you can apply again. Good luck and I'm sorry this happened to you.

[newacct]

The date an application is considered filed is the "received date". In your case, it was in January 2021, and as Enub4 noted, your category and priority date could not file AOS in January. There was no error. What date you mailed it doesn't matter. I don't know what date your package was delivered to USCIS; usually the "received date" is no more than a few days off from when the package was delivered; perhaps it just took a long time to get delivered due to mail delays around Christmas. In any case, as Enub4 noted, you are eligible to file again in March (this month).

[Enub4]

I didn't expect a package to delay 1 month to be delivered, I guess if OP sent it via USPS during the holiday this could be the case.

senthu did you send your package via USPS? When it was delivered? Did USCIS charged your card or cashed the checks? I wonder if you need to pay again.