n b2bi, if we face such an error while processing the INBOUND(Partner-->customer) file via AS2(HTTP&HTTPS) connection then we can fix it by doing the below.

PROBLEM

-- Failure: Message cannot be re-routed because the receiving party is not configured for re-routing.

RESOLUTION

1. First resolution would be to add the routing ID into your system.

--Go to the specific partner and click on the Routing IDs link.

---Type the routing ID in the Routing ID:* text field.

---Click the Add button.

2.Second resolution would be to check the subject header.

---In details of the file received, check message attributes.

---If the subject header is the same as the SENDER routing ID then the system will interpret it as RECEIVER routing ID

---Ask the partner to change the Subject header (Example: RECEIVER routing ID or any text or blank)

3.Third resolution if the above two are fine then add settings to system properties:

---Go to the system properties page but using the following URL:

http://[servername]:6080/ui/core/SystemProperties

---Set the actions.RejectOnRerouteErrors setting to false.

Note: 3rd option will be reflected globally i.e., for all communities and partners.
So third option must be applied only when changes are required globally.

Please feel free to add/modify anything quoted above.