Step 1 Check the forwarded-to number configured by the customer. The number is in the 9XXXXX format, which is correct.
Step 2 Make a call to user D directly as user A. The call is successfully connected. Carrier 2 can recognize user A.
Step 3 Check the outgoing call rights of user B. User B has the inter and local outgoing calls rights, which are the same as the rights of the outgoing call prefix for the R2 trunk. User B can directly make calls to user D.
Step 4 Since user A's call is connected through the VU switchboard, check the VU prefix. The VU prefix has only the inter right. Run the config modify prefix dn xxxx vuoutgoingright inter&local command to add the local outgoing call right for the prefix.
Step 5 Check software parameter 378. Default value 0 is used. Run the config softargu type 378 value 1 command to set software parameter 378 to 1, and the problem is solved.