btw, after such diagnosis efforts, I really feel the logs need to be improved. It's so misleading right now. Look at the *only* error message,[Thu May 05 18:12:29.915467 2016] [authn_dbm:error] [pid 9107:tid 140031532377856] (20019)DSO load failed: [client 127.0.0.1:54442] AH01754: could not open dbm (type DB) auth file: /home/tixu/httpd-2.4.20-bin/dbm-auth-fileIt tells that the auth file cannot be opened. That's all the confusion...But it has nothing to do with the auth file. The error is caused by the failure of loading the DSO... At least, httpd should print out the DSO file it tried to load!