Hard cuestion but not impossible to find answer

[checovv]

they have several machines at the shop i work , for the past 2 weeks we been trying to connect machines with pcs with a esp-16 mi serial hub instead the switcher we been using for years , we almost finished the only thing we need is transfers the programs for the cnc machines to the pcs , pcs can send files to the cncs but can receive them from cnc .
Port in the esp-serial hub says open when receiving.

we used Cimco editor to send and receive.

does anyone knows what else to try.

thanks