Apple Pay Payment certificate is not trusted

Question

I am working on implementing Apple Pay in my ios app, For that I tried to create certificates on the apple account.

I followed this setting_up_apple_pay_requirements link.

and followed the exectly these three steps

1.) Create a merchant ID.

2.)Create a Payment Processing certificate.

3.) Enable Apple Pay in Xcode.

But in my key chain when i added the created certificate, then it is showing "Apple Pay Payment Processing:"merchent id" certificate is not trusted"

Thanks in advance