Fix Exchange 2010 Hybrid Migration

I’m running a live Exchange 2010 SP3 server that should be in hybrid mode with Microsoft 365, but the MRS Proxy has stopped responding and my mailbox moves are stalled. Since the problem surfaced, OWA, ECP and ActiveSync won’t even present a login screen—browsers go straight to a 440 Login Timeout. Outlook (MAPI) continues to function, so mail flow must remain untouched while repairs are made. The breakage appeared after a set of configuration tweaks, not after Windows Update, so I suspect something in IIS, virtual directory settings or authentication got out of sync. I have already burned many hours chasing AI-generated fixes and can’t keep circling. I need an Exchange specialist who can: • Restore MRS Proxy so hybrid mailbox migrations resume • Bring OWA, ECP and ActiveSync back online if required for the migration. Acceptance criteria: successful test migration to 365 If you have deep hands-on experience with Exchange 2010 SP3 hybrid deployments, IIS, and troubleshooting HTTP 440/500 issues, let’s move quickly—this is a production box.