Dean's custom workflow actions work in one portal but fail with a timeout error ('connected app took too long to respond') when the app is installed in other portals, despite the endpoint being responsive.

While no specific solution is provided in the thread, the timing coincides with a HubSpot issue regarding the callback completion endpoint (see messages from Scott Hemmeter [231277] & Lew Talon [232659]). This HubSpot-side issue caused similar failures and timeouts for custom actions and was resolved by HubSpot reverting a change.