Failed to invoke procedure `apoc.import.graphml`: Caused by: java.lang.NullPointerException

Hi! I'm using Neo4j community edition 3.5.3 and APOC I try to import data from a graphml-file, using

CALL apoc.import.graphml("/path/to/file.graphml", {batchSize: 10000, readLabels: true, storeNodeIds: true, defaultRelationshipType:"RELATED"});

but I get the following exception:

Failed to invoke procedure apoc.import.graphml: Caused by: java.lang.NullPointerException

I'm not able to find anything more about the exception. The neo4j.log and the debug.log does not contain anything relevant. Can anyone tell me where to look, or how to turn on more logging?

Kind regards, H├ągen