TestPlansAndSuitesMigrationConfig exception

[f14play]

I'm getting this exception when running TestPlansAndSuitesMigrationConfig. Test Case 2130995 did get successfully migrated. Exception thrown in VstsSyncMigrator.Core\Execution\MigrationContext\TestPlansAndSuitesMigrationContext.cs
Any clue would be appreciated.

[11:00:39 INF] == Suite Title: Regression Suite hardening =============================
[11:00:39 INF] ===============================================================================================
[11:00:39 INF] == Plan[1/1] Suite[1/2] Cases[0/0] - suiteid[2151971] |
[11:00:39 INF] ===============================================================================================
[11:00:39 INF] == Plan[1/1] Suite[1/2] Cases[0/0] - suiteid[2151971] | Processing StaticTestSuite : 2151971 - Regression Suite hardening
[11:00:40 INF] == Plan[1/1] Suite[1/2] Cases[0/0] - suiteid[0 ] | Saving StaticTestSuite : 0 - Regression Suite hardening
[11:00:42 INF] == Plan[1/1] Suite[1/2] Cases[0/0] - suiteid[2151971] | Suite has 0 test cases
[11:00:42 INF] == Plan[1/1] Suite[1/2] Cases[0/0] - suiteid[2151971] | SAVED StaticTestSuite : 24771 - Regression Suite hardening
[11:00:42 INF] == Plan[1/1] Suite[1/2] Cases[0/0] - suiteid[2151971] | Suite has 1 children
[11:00:42 INF] == Plan[1/1] Suite[1/2] Cases[0/0] - suiteid[2151948] | Processing StaticTestSuite : 2151948 - Regression Suite 2023.2 Hardening
[11:00:42 INF] == Plan[1/1] Suite[1/2] Cases[0/0] - suiteid[0 ] | Saving StaticTestSuite : 0 - Regression Suite 2023.2 Hardening
[11:00:45 INF] == Plan[1/1] Suite[1/2] Cases[ 0/29] - suiteid[2151948] | Suite has 29 test cases
[11:00:45 INF] == Plan[1/1] Suite[1/2] Cases[ 1/29] - suiteid[2151948] | Work item: 2130995
[11:00:45 INF] == Plan[1/1] Suite[1/2] Cases[ 1/29] - suiteid[2151948] | Processing TestCase : 2130995 - Verify new UI fields display on Insurance page for Total loss job.
[11:00:47 INF] 1 Work items received, verifying
[11:00:47 INF] Loading 1 Work Items
[11:07:08 FTL] Error while running TestPlansAndSuitesMigrationContext
System.NullReferenceException: Object reference not set to an instance of an object.
at Microsoft.TeamFoundation.TestManagement.Client.TestSuiteEntry.SetPointAssignments(Guid owner, List1 configs) at Microsoft.TeamFoundation.TestManagement.Client.TestSuiteHelper.ServerAddCasesToSuite(TestSuite parent, IEnumerable1 entries, Int32 toIndex)
at Microsoft.TeamFoundation.TestManagement.Client.TestSuite.OnInsertCases(Int32 index, IEnumerable1 cases, Boolean ignoreDuplicates) at Microsoft.TeamFoundation.TestManagement.Client.TestSuiteEntryCollection.InsertCases(Int32 index, IEnumerable1 cases)
at VstsSyncMigrator.Engine.TestPlandsAndSuitesMigrationContext.AddChildTestCases(ITestSuiteBase source, ITestSuiteBase target, ITestPlan targetPlan) in E:\Temp\Git\ado-migration-tool\src\VstsSyncMigrator.Core\Execution\MigrationContext\TestPlansAndSuitesMigrationContext.cs:line 195
at VstsSyncMigrator.Engine.TestPlandsAndSuitesMigrationContext.ProcessTestSuite(ITestSuiteBase sourceSuite, ITestSuiteBase targetParent, ITestPlan targetPlan) in E:\Temp\Git\ado-migration-tool\src\VstsSyncMigrator.Core\Execution\MigrationContext\TestPlansAndSuitesMigrationContext.cs:line 975
at VstsSyncMigrator.Engine.TestPlandsAndSuitesMigrationContext.ProcessTestSuite(ITestSuiteBase sourceSuite, ITestSuiteBase targetParent, ITestPlan targetPlan) in E:\Temp\Git\ado-migration-tool\src\VstsSyncMigrator.Core\Execution\MigrationContext\TestPlansAndSuitesMigrationContext.cs:line 982
at VstsSyncMigrator.Engine.TestPlandsAndSuitesMigrationContext.ProcessTestPlan(ITestPlan sourcePlan) in E:\Temp\Git\ado-migration-tool\src\VstsSyncMigrator.Core\Execution\MigrationContext\TestPlansAndSuitesMigrationContext.cs:line 850
at VstsSyncMigrator.Engine.TestPlandsAndSuitesMigrationContext.InternalExecute() in E:\Temp\Git\ado-migration-tool\src\VstsSyncMigrator.Core\Execution\MigrationContext\TestPlansAndSuitesMigrationContext.cs:line 126
at MigrationTools._EngineV1.Processors.MigrationProcessorBase.Execute() in E:\Temp\Git\ado-migration-tool\src\MigrationTools_EngineV1\Processors\MigrationProcessorBase.cs:line 46
[11:07:08 ERR] TestPlansAndSuitesMigrationContext The Processor MigrationEngine entered the failed state...stopping run

Here's config json used:
{
"$type": "TestPlansAndSuitesMigrationConfig",
"Enabled": true,
"PrefixProjectToNodes": false,
"OnlyElementsWithTag": null,
"TestPlanQueryBit": "PlanName = 'APD-CONNECT-2023.2'",
"RemoveAllLinks": false,
"MigrationDelay": 0,
"UseCommonNodeStructureEnricherConfig": false,
"NodeBasePaths": [],
"AreaMaps": null,
"IterationMaps": null,
"RemoveInvalidTestSuiteLinks": false,
"FilterCompleted": false
}

Exception is thrown here:

[f14play]

Found answer by adding 3 custom field mappings in config file