https://forge.codesys.com/u/charleskirkland/2026-04-27T07:16:47ZRecent posts by charleskirkland2026-04-27T07:16:47Z2026-04-27T07:16:47Zcharleskirklandhttps://forge.codesys.com/u/charleskirkland/https://forge.codesys.comdce44ff063fbf86303d790793e2f0d557549348e

<div class="markdown_content"><p>It sounds like your TLS setup is basically correct, since the handshake works via OpenSSL, so the issue is likely on the CODESYS side rather than the certificates themselves. From what I’ve seen with the Azure IoT Hub Client SL library, you should double-check that the SAS token is actually being generated and passed correctly to the function blocks (especially wsDeviceSaS) and that the MQTT/HTTPS FB is really triggered cyclically-otherwise the controller won’t initiate the connection at all. </p> <p>Also, make sure DNS, time (NTP), and full certificate chain trust are properly configured on the controller, since IoT Hub authentication depends on them even when using SAS tokens. Another thing worth checking is the library/runtime version-there are reports that certain versions changed behavior and caused connection issues. </p> <p>I’d recommend starting with the official demo project (AzureMQTTDemo) and comparing it step by step with your setup to see what’s missing or not triggered.<br/> <a class="" href="https://speed-stars.co" rel="nofollow">Speed Stars</a></p></div>