for or of?

Please help. Thanks!

In this situation, I believe either preposition can be used. Although of would be the better choice.
Of is used when pertaining to something. In this case the matter of rejection. For would refer to matters of time.

Hopefully, another person can clarify.

https://grammar.yourdictionary.com/vs/of-vs-for-differences-and-proper-grammar-use.html

What Does “For” Mean?
Like “of,” there are many similar ways to define “for.” In general, the word “for” means:

The purpose/reason, destination, recipient, or amount of something

Examples Using “For” in a Sentence
Keep in mind that “for” usually indicates a purpose.

Is that cookie for me?I’m asking if I am or will be the recipient of the cookie.
We could substitute white fish for crab meat.The purpose of the fish is to replace the crab meat.
She is speaking for him.The reason she’s talking is because he can’t or won't.
We protest for climate change.The purpose of the protest is to promote climate change awareness.
That vigil was for the people who died in the fire.The recipients of the vigil were the people who died.
Did you look in the drawer for your glasses?The reason why you would look in the drawer is to find the glasses.
For Valentine’s Day I always buy chocolate.The purpose of buying chocolate is Valentine’s Day.
He saved a seat for his best friend.The person who gets the seat is his best friend.