I have just migrated to joomla 2.5, Ive  reinstalled same the parameters than the one on Joomla 1.5 but onthis one I get this error display on frontend

Any help will be really nice

Thanks in advance
Greg

I would make sure that the permissions on your cache and tmp directories are fully open.

You might also see if your get the same 403 just trying to hit the url directly from your server.  They may have your IP blocked or something.

Hi,

Cache and tmp directories are 755
and my IP is not blocked because the same feed is working on my other website under joomla1.5 located on same server.

Any other idea?

Maybe it is restricted from accessing URLs through the allow_url_fopen option within php.ini.
You need to alter your php.ini to Enable this option.