SSL error has occured - no secure connection could be made - happens regulary since (ios App with Azure webservice) since mid May 2022

Peter V 6 Reputation points
2022-06-24T10:25:12.21+00:00

Hi

We have an app (ios) that communicates with Azure WebApp backend working on TLS1.2
Since mid May we recieve complants from our customer that the connection fails.
This happens regulary and almost of the time when using 3G/4G cellular data.
I can simulate this issue (on 4G with good connection)

The customer can use the app but after some API requests we get an exception:

NSLocalizedDescription=NSURLErrorDomain Code=-1200 "An SSL error has occurred and a secure connection to the server cannot be made., NSErrorFailingURLKey=https://sxxxx.azurewebsites.net./api/AppRequest., NSUnderlyingError=0x2831ff810 {Error Domain=kCFErrorDomainCFNetwork Code=-1200 "(null)" UserInfo={_kCFStreamPropertySSLClientCertificateState=0, _kCFNetworkCFStreamSSLErrorOriginalValue=-9816, _kCFStreamErrorDomainKey=3, _kCFStreamErrorCodeKey=-9816, _NSURLErrorNWPathKey=satisfied (Path is satisfied), viable, interface: pdp_ip0, ipv4, ipv6, dns, expensive}}, _kCFStreamErrorCodeKey=-9816}

We connect directly to domain from azurewebsites.net (we don't use online custom domain).

To inform (testcase):
I have rebuild our app and made the same WebAPI availlable on our Win2019 server, then this issue is gone, it works perfectly. No SSL errors..
The azure WebApp is located on the same country (Germany) like our win2019 server.

We don't use client authentication.

Any idea's what is wrong?

Regards
Peter.

Azure App Service
Azure App Service
Azure App Service is a service used to create and deploy scalable, mission-critical web apps.
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  1. Peter V 6 Reputation points
    2022-06-24T14:46:17.167+00:00

    Hi

    Just found the issue.
    The Azure app was configured for HTTP1.1, we have changed to HTTP2 and the problem is fixed now.

    Regards,

    1 person found this answer helpful.
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