I had the same problem although I was using PEAP. I have implemented a temporary workaround inspired by the fix used by the geteduroam app. They chose to set a trusted server name instead of supplying a certificate.
eapSettings.username = username;
eapSettings.password = password;
eapSettings.supportedEAPTypes = [NSArray arrayWithObjects:[NSNumber numberWithInteger:NEHotspotConfigurationEAPTypeEAPPEAP], nil];
eapSettings.outerIdentity = @"anonymous";
eapSettings.trustedServerNames = @[@"OUR-DOMAIN"];
You can find the Geteduroam tag with their fix here: https://github.com/geteduroam/ionic-app/releases/tag/v1.0.21
Topic:
App & System Services
SubTopic:
Networking
Tags: