Error 502.3 (Bad Gateway) when two reverse proxies used

I have server A and server B both with IIS installed and configured as reverse proxies. Server A is supposed to route requests to Server B, and server B is supposed to route requests to Server C (with WebLogic services).

This was tested OK with a browser:

Client (browser on Server B) -> Server B (IIS Reverse Proxy) -> Server C (WebLogic)

But when I tested the below with a browser, I am getting HTTP Error 502.3 (Bad Gateway) with error code 0x80072efe, and error message "The connection with the server was terminated abnormally". The reverse proxy configurations for both Server A and B are the same except for the IP address of the destination server.

Client (browser on Server A) -> Server A (IIS Reverse Proxy) -> Server B (IIS Reverse Proxy) -> Server C (WebLogic)

When I re-configured Server A reverse proxy to route requests directly to Server C, as below, it worked fine too.

Client (browser on Server A) -> Server A (IIS Reverse Proxy) -> Server C (WebLogic)

For the Bad Gateway error when both servers A and B are used, I can't find any error in the log files in both servers. I also can't find anything in the access logs of server B.