Why are some stores rejecting taking coupons printed on home printers?

I suppose it is because they have no way to verify that they are genuine.
Would you accept self printed money?

Call/write the companies that are emailing the coupons and tell them that stores aren’t accepting them. Then find stores that are accepting them and shop there.

I’ve only had issues with stores not accepting printed coupons when the coupon wouldn’t scan.

I did not know this was the case. I have not had any stores do that.

When online coupons first came out, there was a good bit of coupons that were found to be fake. Some retailers stopped taking the printed coupons at that point and never resumed taking them. You could ask to speak with a manager at your store and explain the situation. I would also do what @theichibun recommended and let the company know that you are having a problem using your coupon.

Most of the stores that reject the coupons are owned by East Indians. i understand the situation with the coupons maybe being a fraud or a remake. but, these are stores i have used coupons for many months. i am known to these people on a first-name basis. i think maybe i should contact Marlboro and advise them.

They are lazy.

Mexicans.