Check the environmental variable and SP_SYS_HOST_NAME, and make sure the hostname and IP are correctly are resolving.
1. Activate SharePlex to create the new correct routing specification and this will create new routing spec in rim directory.
This will increase the activation id+1.
For example base on the event_log file on problem description section:
/vardir/rim/RS.40447af4.47
2. Shutdown SharePlex and copy this routing spec to missing routing spec.
In this example 46
cp /vardir/rim/RS.40447af4.47 /vardir/rim/RS.40447af4.46
3. Start SharePlex and make sure that the sp_cop binds to the correct SP_SYS_HOST_NAME.
This should resolve the routing issue for the Read and Export processes, and messages should start to replicate again.