Developer certificate enrollment error when implementing the push function of monaca

I am developing ios at Monaca.
I am trying to work with Nifty cloud to send push notifications, but when I set up the ios build, I am having trouble registering the developer certificate.
When creating developer certificates in ios devcenter,
Apple Push Notification service SSL (Sandbox)
If you select this, you can issue the certificate itself, but when you upload the certificate on Monaca's ios build configuration screen, you get a photo-like error.
How can I register my certificate without any errors??
Or is it possible to connect Monaca with nifty cloud mBaaS in other ways??