Wings transforms IBM i green-screens into modern, attractive, browser pages. It generates Web-based display files created directly from your green-screen display file definitions. Wings also includes a browser-based 5250 emulator to display any screens you haven't yet modernized with Wings.
The other day a customer reported a puzzling challenge with his Wings application. His application was working great on two of three IBM i boxes (all three had the same product and IBM i OS versions installed). When used against the third IBM i, however, Wings would not connect to it. Because it wasn't connecting there weren't any job logs we could investigate.
Alas, ASNA R&D came to the rescue and recognized these values from the error's call stack:
Error = dgEiTLNTCNCT
SysytemError = 3021
These values indicate that the IBM i's Telnet server, which Wings' browser uses, is either not started or not communicating on port 23.
The IBMi Telnet Server must be running in order to start Wings jobs. Additionally, the Telnet Server must be configured to accept non-SSL connections on TCP port 23 (this is typically the default setting). For the security conscious, DG/400 only creates connections to Telnet server from the "loopback” interface address (usually 127.0.0.1 or ::1), so port 23 does not need to be exposed to incoming external addresses.
If you're using Wings and see these error values, use the IBM i's WRKSRVTBLE command to ensure Telnet is running and that is running on port 23, as shown below.