I am able to establish a connection between first and second NodeMCU, but unable to do so for the third nodeMCU. I used the IP address to establish connection. Should I assign a different IP to each nodeMCU so that communication can take place? In the code that I had written, i have taken the same IP for all three NodeMCUs, so communication was possible between 1st nodemcu(in AP mode) and 2nd nodemcu(in STA+AP mode). For the 3rd node mcu the IP taken was different. Can any one suggest what to do next.
The two network interfaces (station and SoftAP) of the middle esp8266 must have different IP address range. If the top esp8266 has SoftAP with 192.168.4.x, set for the SoftAP of the middle esp8266 IP for example 192.168.5.1. Because with same IP address ranges the esp8266 doesn't know to which network do you want to connect a TCP socket or send an UDP message.