How can I open the web service log?

Hi experts,

BYD system, using soap test web service, after I click run, the result is xml.

<faultstring xml:lang="en">Web service processing error; more details in the web service error log on provider side (UTC timestamp 20160628004134; Transaction ID 00163E19C51F1ED68F992203A13402EA)</faultstring>

How can I open the log? Where is the log file?

Thanks.