Problems reading xlsx file with apache-poi

I have a strange error reading an xlsx file, on my windows computer I have no problem, instead on heroku it gives me the following error: unable to parse shared strings table. Obviously the file I try to read is the same.

My code:

private fun readExcelContent(file: InputStream): Sequence<Row> {
    val pkg = OPCPackage.open(file)
    pkg.use {
        val reader = XSSFReader(pkg)
        val sst = reader.sharedStringsTable
        val parser = XMLHelper.newXMLReader()
        val handler = ExcelSheetHandler(sst)
        parser.contentHandler = handler
        val sheet = reader.sheetsData.next()
        val source = InputSource(sheet)
        try {
            parser.parse(source)
        } catch (e: ConsecutiveBlanksException) {
            logger.info("The file contained several consecutive blank lines that have been skipped.")
        }

        return handler.content.asSequence()
    }
}

stacktrace:

Feb 16 21:56:15.622 scheduler.1 at java.xml/com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:327) ~[na:na] Feb 16 21:56:15.622 scheduler.1 at java.xml/com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:400) ~[na:na] Feb 16 21:56:15.622 scheduler.1 at java.xml/com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.fatalError(ErrorHandlerWrapper.java:178) ~[na:na] Feb 16 21:56:15.622 scheduler.1 at java.xml/com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:204) ~[na:na] Feb 16 21:56:15.622 scheduler.1 Caused by: org.xml.sax.SAXParseException: The element type "t" must be terminated by the matching end-tag "". Feb 16 21:56:15.622 scheduler.1 ... 36 common frames omitted Feb 16 21:56:15.622 scheduler.1 at org.apache.poi.xssf.model.SharedStringsTable.readFrom(SharedStringsTable.java:123) ~[poi-ooxml-4.1.2.jar!/:4.1.2] Feb 16 21:56:15.622 scheduler.1 at org.openxmlformats.schemas.spreadsheetml.x2006.main.SstDocument$Factory.parse(Unknown Source) ~[poi-ooxml-schemas-4.1.2.jar!/:4.1.2] Feb 16 21:56:15.622 scheduler.1 at org.apache.xmlbeans.impl.schema.SchemaTypeLoaderBase.parse(SchemaTypeLoaderBase.java:345) ~[xmlbeans-3.1.0.jar!/:na] Feb 16 21:56:15.622 scheduler.1 at org.apache.xmlbeans.impl.store.Locale.parseToXmlObject(Locale.java:1259) ~[xmlbeans-3.1.0.jar!/:na] Feb 16 21:56:15.622 scheduler.1 at org.apache.xmlbeans.impl.store.Locale.parseToXmlObject(Locale.java:1272) ~[xmlbeans-3.1.0.jar!/:na] Feb 16 21:56:15.622 scheduler.1 at org.apache.xmlbeans.impl.store.Locale$SaxLoader.load(Locale.java:3448) ~[xmlbeans-3.1.0.jar!/:na] Feb 16 21:56:15.622 scheduler.1 Caused by: org.apache.xmlbeans.XmlException: error: The element type "t" must be terminated by the matching end-tag "". Feb 16 21:56:15.622 scheduler.1 ... 34 common frames omitted Feb 16 21:56:15.622 scheduler.1 at org.apache.poi.ooxml.POIXMLFactory.createDocumentPart(POIXMLFactory.java:61) ~[poi-ooxml-4.1.2.jar!/:4.1.2] Feb 16 21:56:15.622 scheduler.1 at org.apache.poi.xssf.model.SharedStringsTable.(SharedStringsTable.java:111) ~[poi-ooxml-4.1.2.jar!/:4.1.2] Feb 16 21:56:15.622 scheduler.1 at org.apache.poi.xssf.model.SharedStringsTable.readFrom(SharedStringsTable.java:134) ~[poi-ooxml-4.1.2.jar!/:4.1.2] Feb 16 21:56:15.622 scheduler.1 Caused by: java.io.IOException: unable to parse shared strings table Feb 16 21:56:15.622 scheduler.1 ... 29 common frames omitted