Hi everyone 👋
I’m running into a persistent SSL issue on iOS where the app fails to establish a secure HTTPS connection to our backend APIs.
The same endpoints work fine on Android and web, but on iOS the requests fail with:
Error Domain=NSURLErrorDomain Code=-1200
"An SSL error has occurred and a secure connection to the server cannot be made."
UserInfo={
NSLocalizedDescription = "An SSL error has occurred and a secure connection to the server cannot be made.";
_kCFStreamErrorDomainKey = 3;
_kCFStreamErrorCodeKey = -9802;
}
🔍 What I’ve Checked:
The servers use valid, trusted SSL certificates from a public CA
TLS 1.2 and 1.3 are enabled
The intermediate certificates appear correctly configured (verified using SSL Labs)
The issue happens on our customer's end. (Got it via Sentry)
Note: We recently removed NSAppTransportSecurity(NSAllowsArbitraryLoads) on our app, since all the endpoints use valid HTTPS certificates and standard configurations.
❓ Questions:
Are there additional SSL validation checks performed by iOS when ATS is enabled?
Has anyone seen similar behaviour, where valid certificate chains still trigger SSL errors?
Any insights or debugging suggestions would be greatly appreciated 🙏
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