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i4scada Knowledge Base

Web Service Interface Error Codes


Check out this article and learn more details about the i4scada Web Service Interface error codes.

InetPro webservice

Up to now the following general web service related return codes are defined:

Error Code



Invalid Channel Id


Communication Error


DCOM Error


Error Creating new Channel


Error Accessing the Data Base

-6, -7

License Error


Invalid Client Name or IP Address


Invalid Channel ID


Invalid session password


Unspecified Error

Besides this general web service error codes, the following related error codes can be returned by specific web methods:

Error Code



User login failed (Login)

This can be caused by an invalid username or password.

The usual workaround is to check the user configuration and verify that the login exists and the password is correct.


No user logged in (Write)

This error occurs when a user tries to write a secured signal without being logged in. Signals can be configured to be secure so you need to have a login that is allowed to write those specific signals.

The workaround here would be to login before writing the signal, or if it is the case, remove the write protection for the signal.


Insufficient user authorizations (Write)

This is similar to error -4094. This happens if the user is logged in but doesn’t have enough permissions to write the signal. This is normal if the user shouldn’t be able to do this operation. If he should, then the permissions should be updated so that he can write it, or the signal write protection should be removed.


User already logged on (Login)


Invalid user password (Login)


Max user count reached (Login)


Unspecified server error (Login, Write)


Signal is write protected (Write)


Expired password (Login)


Invalid command syntax (Login)


The number of failed logins exceeded. Username blocked. (Login)


Cannot obtain current logged in user name (Login)


Signal is not registered in Server or Server is not running (Login, Write)

The WriteSignal method can also return some OPC related error codes. Please refer here to the documentation of the OPC servers.