Password with a colon fails basic auth?

I'm using basic auth. If my password contains a colon, I seem to get a failure to authenticate. Are colons not allowed in a password? How I'm authenticating:

DefaultHttpClient client = new DefaultHttpClient();
HttpRequestInterceptor preemptiveAuth = new HttpRequestInterceptor() {
    ...
};
client.addRequestInterceptor(preemptiveAuth, 0);
client.getCredentialsProvider().setCredentials(
  new AuthScope("example.com", 443),
  new UsernamePasswordCredentials("me", "password:test"));

Passwords without a colon always work. Passwords with a colon always fail. Do I have to escape the password somehow before handing it to the UsernamePasswordCredentials class constructor? I know basicauth uses the username/password separated by a colon, then base64 encoded, is that what the problem is here?

Thanks

---- Update ------

Thanks all, yes was a problem in the server I was communicating with!