Why do I get a "You do not have permission..." message when I try to log in to ILL?
We have seen other users have this problem when they have the Zotero plugin installed in their browser. Certain proxy re-direction settings in Zotero can prohibit users from arriving at the correct URL for their ILL account login. Cowles Library does not use a proxy server for ILL authentication, so you shouldn't need Zotero to send you through a proxy.
If you have the Zotero plugin, temporarily disable proxy redirection in the plugin preferences, then try accessing your ILL account through the library's website again. Information about Zotero proxy preferences is available at https://www.zotero.org/support/preferences/proxies.