Error: "Can not construct an ExternalCustomField with null arguments"

[Caslav Mitic]

During import of CSV file, I try to create Custom filed:

On Submit I get this dialog:

and on  "Retry", it continue to this:

But on import I get error: "Can not construct an ExternalCustomField with null arguments."

My csv file:
Summary,Description,FBID,FBSubID,Project
Tilføjelse af nyt felt,Tilføjelse af nyt felt 'XXX',4218,48353,TEST-projekt
Tilføjelse af nyt felt,CRQM desc,4218,48354,TEST-projekt

Log file:

2025-05-07T12:26:40,675 INFO - Import started by xxx@xxx.com using com.atlassian.jira.plugins.importer.imports.csv.CsvDataBean
2025-05-07T12:26:40,676 INFO - Skipped importing of Users
2025-05-07T12:26:40,676 INFO - Retrieving projects...
2025-05-07T12:26:40,676 INFO - Project ExternalProject{id='null', key='Cccc', externalName='null', name='Cccc Test'} exists and found correctly.
2025-05-07T12:26:40,676 INFO - ------------------------------
2025-05-07T12:26:40,676 INFO - Importing: Versions
2025-05-07T12:26:40,676 INFO - ------------------------------
2025-05-07T12:26:40,676 INFO - Only new items will be imported
2025-05-07T12:26:40,676 INFO - ------------------------------
2025-05-07T12:26:40,676 INFO - Finished Importing : Versions
2025-05-07T12:26:40,676 INFO - ------------------------------
2025-05-07T12:26:40,676 INFO - ------------------------------
2025-05-07T12:26:40,676 INFO - Importing: Components
2025-05-07T12:26:40,676 INFO - ------------------------------
2025-05-07T12:26:40,676 INFO - Only new items will be imported
2025-05-07T12:26:40,676 INFO - ------------------------------
2025-05-07T12:26:40,676 INFO - Finished Importing : Components
2025-05-07T12:26:40,676 INFO - ------------------------------
2025-05-07T12:26:40,676 INFO - Retrieving custom fields...
2025-05-07T12:26:40,676 INFO - ------------------------------
2025-05-07T12:26:40,676 INFO - Importing: Issues
2025-05-07T12:26:40,676 INFO - ------------------------------
2025-05-07T12:26:40,676 INFO - Only new items will be imported
2025-05-07T12:26:40,676 WARN - Found 2 'External issue ID' custom fields. Some issues may be imported twice. Found custom fields: [External issue ID, External issue ID]
2025-05-07T12:26:40,678 INFO - Importing issue: [externalId='autoid-2802159704253243748', summary='Tilføjelse af nyt felt']
2025-05-07T12:26:40,678 INFO - ------------------------------
2025-05-07T12:26:40,678 INFO - Finished Importing : Issues
2025-05-07T12:26:40,678 INFO - ------------------------------
2025-05-07T12:26:40,678 ERROR - Unexpected failure occurred. Importer will stop immediately. Data may be in an unstable state
java.lang.IllegalArgumentException: Can not construct an ExternalCustomField with null arguments.
	at com.atlassian.jira.plugins.importer.external.beans.ExternalCustomField.<init>(ExternalCustomField.java:30) ~[jira-importers-plugin-13.0.4-mnstr-7001-2.jar:?]
	at com.atlassian.jira.plugins.importer.imports.importer.impl.DefaultJiraDataImporter.verifyCustomFieldOrCreate(DefaultJiraDataImporter.java:1235) ~[jira-importers-plugin-13.0.4-mnstr-7001-2.jar:?]
	at com.atlassian.jira.plugins.importer.imports.importer.impl.DefaultJiraDataImporter.importExternalCustomFields(DefaultJiraDataImporter.java:1278) ~[jira-importers-plugin-13.0.4-mnstr-7001-2.jar:?]
	at com.atlassian.jira.plugins.importer.imports.importer.impl.DefaultJiraDataImporter.createIssue(DefaultJiraDataImporter.java:932) ~[jira-importers-plugin-13.0.4-mnstr-7001-2.jar:?]
	at com.atlassian.jira.plugins.importer.imports.importer.impl.DefaultJiraDataImporter.importIssues(DefaultJiraDataImporter.java:807) ~[jira-importers-plugin-13.0.4-mnstr-7001-2.jar:?]
	at com.atlassian.jira.plugins.importer.imports.importer.impl.DefaultJiraDataImporter.doImport(DefaultJiraDataImporter.java:419) [jira-importers-plugin-13.0.4-mnstr-7001-2.jar:?]
	at com.atlassian.jira.plugins.importer.imports.importer.impl.ImporterCallable.call(ImporterCallable.java:26) [jira-importers-plugin-13.0.4-mnstr-7001-2.jar:?]
	at com.atlassian.jira.plugins.importer.imports.importer.impl.ImporterCallable.call(ImporterCallable.java:15) [jira-importers-plugin-13.0.4-mnstr-7001-2.jar:?]
	at com.atlassian.jira.task.TaskManagerImpl$TaskCallableDecorator.call(TaskManagerImpl.java:528) [classes/:?]
	at com.atlassian.jira.task.TaskManagerImpl$TaskCallableDecorator.call(TaskManagerImpl.java:486) [classes/:?]
	at java.util.concurrent.FutureTask.run(FutureTask.java:264) [?:?]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539) [?:?]
	at java.util.concurrent.FutureTask.run(FutureTask.java:264) [?:?]
	at com.atlassian.jira.task.ForkedThreadExecutor$ForkedRunnableDecorator.run(ForkedThreadExecutor.java:216) [classes/:?]
	at java.lang.Thread.run(Thread.java:840) [?:?]
2025-05-07T12:26:40,678 INFO - No issues need to be reindexed.

[Marc - Devoteam · Accepted solution]

Hi @Caslav Mitic 

Welcome to the community.

I suspect you are running an on-prem Jira, no Cloud.

This error is classified as an unresolved Bug, see; https://jira.atlassian.com/browse/JRASERVER-77888 

[Caslav Mitic]

Hi Marck.
Yes, we have Jira on-prem.

Thank you.

BR <caslav />