The Zotero Connector tries to save you time by automatically detecting and saving proxies. Unfortunately, those saved settings conflict with the authentication method MCPHS Smart Search uses. It may also cause issues with accessing content from other library subscriptions.
For MCPHS Smart Search, you may see EBSCO's "Select Resources" page instead of what you wanted. The wording is slightly different on a Mac than on a Windows computer.
Click "Don't proxy this site" to fix it for a short time.
For a longer fix, click "Proxy Settings," make sure you are on the "Proxies" page, and deselect "Enable proxy redirection."