An error occurred while trying to write to the data store. No values have been written. Details: could not insert: (APNX-1-4208-004)

I believe you will find more detail (including the specific column(s) that are failing to insert and usually the reason why) in the Appian System Logs, specifically tomcat-stdout.log.

Thanks Mike! 

I got the issue in log file.

how to get to appian system logs?

how did you solve it?

https://docs.appian.com/suite/help/21.3/Logging.html

For Cloud Appian installation, once you reproduced the error immediately look for the file with name of today's date tomcat-stdOut.log.2021-09-08 in https://environment/suite/logs .  

In my experience so far I've had this issue come up when we try to write the empty cdt in write to DB .It can be solved by passing not null cdt to write to DB. Also as suggested please look for log for more details,  I know this doesn't assist much, but it's a place to start.

Hello gayathris. How can i check the logs? 

Logs can be found here:

Obviously there are a wide range of logs for different purposes. For the use case in this thread you're looking for the "stdOut" log, like this:

Thank you Stewart Burchell

Can you explain this a little bit? I have passed a CDT like this: 
= {
{
entity: cons!CSV_DATA,
data: { pv!tmp_CsvData }
},
{
entity: cons!IMPORT_DOCUMENT,
data: 'type!{urn:com:appian:types:RCP}Temp_ImportDocument'(
ImportFk: pv!tmp_cdt_Import.id,
DocIdNumber: pv!param_doc,
fileExtension: document(pv!param_doc, "extension"),
fileSize: document(pv!param_docu "size"),
isActive: true(),
createdBy: user(loggedInUser(), "firstName") & " " & user(loggedInUser(), "lastName"),
createdOn: now(),
modifiedOn: now()
)
}
}

What I am doing wrong on this? Also got this error in log file: "

com.appiancorp.process.runtime.activities.MultiWriteToDataStoreSmartService.writeToMultipleDataStoreEntities(MultiWriteToDataStoreSmartService.java:125)

"

Please suggest