Hi,
We haven't come across this issue before, however some posts over the web suggest a possible problem in usage of response.redirect inside ajax call and maybe a connection with Ext.js usage - e.g. in
this stackoverflow.com post.
It could be related to redirection and wrong usage of try/catch.
We would need to know what's the external API and what exactly is called there in order to help you with this. Any further info would be appreciated.
Regards,
Zdenek