For example Poetry en->es:
Cxserver response is
TypeError: Cannot read property 'attributes' of null at Parser.onopentag (/srv/deployment/cxserver/deploy-cache/revs/3cb9a219599c91befba2a8adc581a6a32def0595/src/lib/lineardoc/Parser.js:132:29) at emit (/srv/deployment/cxserver/deploy-cache/revs/3cb9a219599c91befba2a8adc581a6a32def0595/node_modules/sax/lib/sax.js:640:35) at emitNode (/srv/deployment/cxserver/deploy-cache/revs/3cb9a219599c91befba2a8adc581a6a32def0595/node_modules/sax/lib/sax.js:645:5) at openTag (/srv/deployment/cxserver/deploy-cache/revs/3cb9a219599c91befba2a8adc581a6a32def0595/node_modules/sax/lib/sax.js:841:5) at Parser.write (/srv/deployment/cxserver/deploy-cache/revs/3cb9a219599c91befba2a8adc581a6a32def0595/node_modules/sax/lib/sax.js:1404:13) at Apertium.buildSourceDoc (/srv/deployment/cxserver/deploy-cache/revs/3cb9a219599c91befba2a8adc581a6a32def0595/src/lib/mt/MTClient.js:368:10) at Apertium.translateHtml (/srv/deployment/cxserver/deploy-cache/revs/3cb9a219599c91befba2a8adc581a6a32def0595/src/lib/mt/MTClient.js:80:8) at Apertium.translate (/srv/deployment/cxserver/deploy-cache/revs/3cb9a219599c91befba2a8adc581a6a32def0595/src/lib/mt/MTClient.js:43:16) at MWReference.<anonymous> (/srv/deployment/cxserver/deploy-cache/revs/3cb9a219599c91befba2a8adc581a6a32def0595/src/lib/translationunits/MWReference.js:48:60) at next (native) at resume (/srv/deployment/cxserver/deploy-cache/revs/3cb9a219599c91befba2a8adc581a6a32def0595/src/lib/util.js:277:21) at resumeNext (/srv/deployment/cxserver/deploy-cache/revs/3cb9a219599c91befba2a8adc581a6a32def0595/src/lib/util.js:287:26) at /srv/deployment/cxserver/deploy-cache/revs/3cb9a219599c91befba2a8adc581a6a32def0595/src/lib/util.js:289:3 at spawn (/srv/deployment/cxserver/deploy-cache/revs/3cb9a219599c91befba2a8adc581a6a32def0595/src/lib/util.js:272:9) at MWReference.adapt (/srv/deployment/cxserver/deploy-cache/revs/3cb9a219599c91befba2a8adc581a6a32def0595/src/lib/util.js:301:10) at Doc.<anonymous> (/srv/deployment/cxserver/deploy-cache/revs/3cb9a219599c91befba2a8adc581a6a32def0595/src/lib/lineardoc/Doc.js:270:36)