Error processing HTTP request header

It looks like this error occurs when you send an HTTPS request to a Tomcat server running an HTTP listener.

I got a similar error message from a sample Tomcat Docker image (

docker run -it --rm -p 8888:8080 tomcat:alpine

curl -Ivk https://localhost:8888/

21-Mar-2019 00:36:25.559 INFO [http-nio-8080-exec-8] org.apache.coyote.http11.Http11Processor.service Error parsing HTTP request header
 Note: further occurrences of HTTP header parsing errors will be logged at DEBUG level.
 java.lang.IllegalArgumentException: Invalid character found in method name. HTTP method names must be tokens
    at org.apache.coyote.http11.Http11InputBuffer.parseRequestLine(Http11InputBuffer.java:428)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:684)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)

You could confirm this by removing the serverssl profile from the VIP in question.

You could also try connecting to ports 8443 and 8444 on your Tomcat hosts to verify that they are in fact configured to accept HTTPS connections.

If neither of these resolves the issue, you could try sharing a sanitized version of your VIP configuration, along with confirmation that the Tomcat servers are accepting HTTPS connections.