fix(webhooks): return empty 200 for Slack to close modals cleanly (#3492)

* fix(webhooks): return empty 200 for Slack to close modals cleanly

* fix(webhooks): add clarifying comment on Slack error path trade-off

Author: waleedlatif1

apps/sim/lib/webhooks/processor.ts

@@ -1166,6 +1166,12 @@ export async function queueWebhookExecution(
       })
     }
 
+    // Slack requires an empty 200 for interactive payloads (view_submission, block_actions, etc.)
+    // A JSON body like {"message":"..."} is not a recognized response format and causes modal errors
+    if (foundWebhook.provider === 'slack') {
+      return new NextResponse(null, { status: 200 })
+    }
+
     // Twilio Voice requires TwiML XML response
     if (foundWebhook.provider === 'twilio_voice') {
       const providerConfig = (foundWebhook.providerConfig as Record<string, any>) || {}
@@ -1211,6 +1217,12 @@ export async function queueWebhookExecution(
       )
     }
 
+    if (foundWebhook.provider === 'slack') {
+      // Return empty 200 to avoid Slack showing an error dialog to the user,
+      // even though processing failed. The error is already logged above.
+      return new NextResponse(null, { status: 200 })
+    }
+
     if (foundWebhook.provider === 'twilio_voice') {
       const errorTwiml = `<?xml version="1.0" encoding="UTF-8"?>
 <Response>