SharePoint 2010 javascript file Access Denied

The sharepoint web site returns content of the sp.core.js file correctly, when accessing the server by computer name, but when using network IP address, the 401.2 Access is denied error is returned. The alternate access mappings are defined correctly. Mapping with IP server network address is set as Default, so it must be working smoothly.

http://thespservcomp:25555/_layouts/sp.core.js?rev=... working correctly http://ift.tt/1DQoUrQ... returns 401.2 Access Denied

In the alternate access mapping section: for Default zone both Internal and Public Urls are set to following http://ift.tt/1EKAtyG

for Custom zone both Internal and Public Urls are set to following http://thespservcomp:25555

Thanks in advance for all your help.