Modscan to 651 Recloser

[ant]

I couldn't figure out which board to post so apologies if wrong board

For 651R, there is currently one tcp connection to source port 50018 to port 502 (see attach screenshot). If another tcp connection with modscan with source port 64623 to port 502, it fails. Wireshark shows modscan try 3 times with SYN and fails. However, with other TCP ports such as http (port 80), multiple simultaneous connections are ok. For port 502, it is only limited to one connection at a time?

On manual, I see below so not sure if this is the case.

The TCP port number is the Modbus TCP registered port 502. Modbus TCP uses the  device IP address as the Modbus identifier and accesses the data in the relay through use of the same function codes and data maps as Modbus RTU.....Modbus RTU is a binary protocol that permits communication among a single master device and multiple slave devices. The communication is half duplex—only one device transmits at a time