Can't receive verification email from my bank

I used my iCloud many times for verifying my bank it sent the code numerous times and than suddenly one day it just stopped receiving the code, my email works fine from what I can see it sends and receives other emails but whenever I send the verification code from my bank nothing pops up in the mail even tho it's been working for a long time and I still have those other emails it won't send me any of my new verification codes.