Why do I have a C next to my EFC?

So I submitted my FAFSA a couple of days ago and it was successfully processed today. However, I went to check my SAR and I have a C next to my EFC. The SAR says that I haven’t registered for selective service which I said I was registered for on my FAFSA because I clicked yes register to me last year when I submitted my FAFSA for the 1st time. I don’t understand why it says that I haven’t registered when I thought I registered last year. What should I do? Should I just register through the sss.gov website to make it a for sure? or wait for my school’s financial aid to bring it up and register then?

I don’t think you should just wait, because your school may not be able to process your awards. Selective service has a page for you to check registration. Do that first.
https://www.sss.gov/Regver/mobile/mVerification.aspx

Ok, Thank you very much. Apparently I wasn’t registered by I already registered.

If you were too young to be registered when you indicated on last year’s FAFSA that you wanted to be registered, you would not have been registered. If you just registered, you can go to www.sss.gov, click “Check Registration,” print out the confirmation that you are registered, and send it to the financial aid office at each school (include an explanation that you had a C flag for Selective Service & this is your documentation that you are now registered).