VadimB joined the community
Had the same problem guys. Spent about a week to find a solution. Implemented ways to restart TCP connection, as described before. Finally called to support NI. Support engineer recomended to check the network properties. The broblem was as follows: my microcontroller (MC) and operator machine (PC) were in defferent subnets. As subnet was tuned to simmiliar fo both MC and PC, the error 66 has varnished, as the problem did. Good luck. Take care of yourself.