OPC UA write failed with X20CP1586 after re-boot


I met the issue with customer client connected with our PLC 1586 using OPC UA.
The AR is C4.90. AS version 4.12.

The issue happened after CPU power-off and power-on.

Before re-boot, we can write a bool value successfully:

After re-boot:

Read Request:

We can not get the response:

Then we somehow get the wrong type when write, actually we write a bool value(the same value):

I guess the issue came from the service fault after reboot, but we can not find the root cause, anyone could help to analyze this, thanks!

The StatusCode: 0x80040000 [BadResourceUnavailable] indicates that the requested resource is currently unavailable. In the context of the OPC UA protocol, this could mean that the node you are attempting to read is currently unavailable, or the current state of the server does not permit this operation.

If you send a ReadRequest immediately after the server restarts, it’s possible that the server has not fully initialized yet, and therefore cannot respond to your request. In this situation, you might need to wait for a while after the server restarts, and send the ReadRequest after the server has completed its initialization.

As a client, after receiving this error message, you should wait for some time and then re-request the data.

That make sense, Thanks!