c3dbfd83_imply_Modbus___Exception_Codes__Meaning
[Exception Code] 10 (0A hex) [Name] Gateway Path Unavailable [Meaning] 
Specialized use in conjunction with gateways, indicates that the gateway was unable to allocate an internal communication path from the input port to the output port for processing the request. Usually means the gateway is misconfigured or overloaded.
Simply Modbus - Exception Codes
Meaning