1. Cannot Connect
- Is address correct:
opc.tcp://<host>:4840/ - Is port occupied
- Is container port exposed
- Did client select correct endpoint (no_security vs secure)
2. Cannot See Any Nodes
Prioritize checking:
- Is AppSubscription created (No subscription = No points routed)
- Is there Telemetry/Attributes data entering this App
TIP
Nodes are created lazily: Only "Points routed to this App" will appear.
3. Value Not Updating / Subscription No Change
- Is update queue dropping (Under high system pressure)
- Did you subscribe to correct variable node
- Is point meta missing causing node not created (Usually created after receiving data)
4. Writeback Failure (BadTypeMismatch/BadNotWritable/BadNotConnected)
Common causes:
- Point access_mode is not Write/ReadWrite
- Client write Variant type mismatch (Current strict type)
- Device/Channel not connected
- Write timeout (writeTimeoutMs or southward write timeout)