ProtocolException: Expected ':status' head

Question

Retrofit network calls fails with a Protocol Exception suddenly in a working app. The app was working till yesterday and today all the network calls fails. The calls works fine with HTTP but fails with HTTPS.

Here is the logs,

java.net.ProtocolException: Expected ':status' header not present
10-18 14:59:01.103 30746-30746/? W/System.err:     at okhttp3.internal.http.Http2xStream.readHttp2HeadersList(Http2xStream.java:262)
10-18 14:59:01.103 30746-30746/? W/System.err:     at okhttp3.internal.http.Http2xStream.readResponseHeaders(Http2xStream.java:145)
10-18 14:59:01.103 30746-30746/? W/System.err:     at okhttp3.internal.http.CallServerInterceptor.intercept(CallServerInterceptor.java:53)
10-18 14:59:01.103 30746-30746/? W/System.err:     at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
10-18 14:59:01.103 30746-30746/? W/System.err:     at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67)
10-18 14:59:01.103 30746-30746/? W/System.err:     at codmob.com.campuswallet.app.ApiClient$1.intercept(ApiClient.java:66)
10-18 14:59:01.103 30746-30746/? W/System.err:     at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
10-18 14:59:01.103 30746-30746/? W/System.err:     at okhttp3.internal.connection.ConnectInterceptor.intercept(ConnectInterceptor.java:45)
10-18 14:59:01.103 30746-30746/? W/System.err:     at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
10-18 14:59:01.103 30746-30746/? W/System.err:     at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67)
10-18 14:59:01.103 30746-30746/? W/System.err:     at okhttp3.internal.cache.CacheInterceptor.intercept(CacheInterceptor.java:109)
10-18 14:59:01.103 30746-30746/? W/System.err:     at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
10-18 14:59:01.103 30746-30746/? W/System.err:     at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67)
10-18 14:59:01.103 30746-30746/? W/System.err:     at okhttp3.internal.http.BridgeInterceptor.intercept(BridgeInterceptor.java:93)
10-18 14:59:01.103 30746-30746/? W/System.err:     at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
10-18 14:59:01.103 30746-30746/? W/System.err:     at okhttp3.internal.http.RetryAndFollowUpInterceptor.intercept(RetryAndFollowUpInterceptor.java:124)
10-18 14:59:01.103 30746-30746/? W/System.err:     at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92)
10-18 14:59:01.104 30746-30746/? W/System.err:     at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67)
10-18 14:59:01.104 30746-30746/? W/System.err:     at okhttp3.RealCall.getResponseWithInterceptorChain(RealCall.java:170)
10-18 14:59:01.104 30746-30746/? W/System.err:     at okhttp3.RealCall.access$100(RealCall.java:33)
10-18 14:59:01.104 30746-30746/? W/System.err:     at okhttp3.RealCall$AsyncCall.execute(RealCall.java:120)
10-18 14:59:01.104 30746-30746/? W/System.err:     at okhttp3.internal.NamedRunnable.run(NamedRunnable.java:32)
10-18 14:59:01.104 30746-30746/? W/System.err:     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
10-18 14:59:01.104 30746-30746/? W/System.err:     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
10-18 14:59:01.104 30746-30746/? W/System.err:     at java.lang.Thread.run(Thread.java:761)

Answer 1

After hours of mess, finally got a solution. Updating Retrofit and Okhttp3 libraries to the latest version did the trick for me.

compile 'com.squareup.okhttp3:okhttp:3.9.0'

compile 'com.squareup.retrofit2:retrofit:2.3.0'

Answer 2

I am using okhttp3 (okhttp-3.4.1), okhttp3 is not very compatible with the HTTP_1.1 protocol and needs to be manually added. you can see Official link

OkHttpClient.Builder builder = new OkHttpClient.Builder();
//protocols
List<Protocol> protocols = new ArrayList<Protocol>();
protocols.add(Protocol.HTTP_1_1);
protocols.add(Protocol.HTTP_2);
builder.protocols(protocols);

Answer 3

Today faced the same problem. The reason was in updating nginx on the server to the latest version (1.13.6). Ask your backend team if they did not update nginx on the server.

nginx changelog - http://nginx.org/en/CHANGES

Answer 4

I am using OkHttp2 (2.7.5) and I solved this issue by forcing the client to use HTTP 1.1 protocol

OkHttpClient client = new OkHttpClient();
client.setProtocols(Arrays.asList(Protocol.HTTP_1_1)); // <- add this line