I had a trigger that fired from webhook, this trigger receive JSON that contain external Id for account object, inside the trigger I do an upsert on account object using the following code

Database.upsert(accountrecord, external_id__c)

but sometimes for unknown reason I got the following exception

System.DmlException: Upsert failed. First exception on row 0; first error: DUPLICATE_VALUE, duplicate value found: External_Id__c duplicates value on record with id: 0011x00000Gc4LI: []

I tried to add SOQL query to retrieve the account record with the external Id I have to testing purpose and I didn't get any records!

System.DmlException: Insert failed. First exception on row 0; first error: CANNOT_INSERT_UPDATE_ACTIVATE_ENTITY, OrderTrigger: execution of AfterUpdate

caused by: System.NullPointerException: Attempt to de-reference a null object

Class.StatusUpdate.Progress: line 25, column 1
Class.OrderTriggerHandler.afterUpdate: line 57, column 1
Class.TriggerHandler.run: line 47, column 1
Trigger.OrderTrigger: line 91, column 1: []


I am getting this error for my test class fail.