API error responses generated by AbuseFilter and SpamBlacklist have changed, as announced here: https://lists.wikimedia.org/pipermail/mediawiki-api-announce/2019-September/000148.html (relevant task: T229539).
It appears you have special handling for the old responses. It should be updated, otherwise it will probably show a generic error message instead of a more specific one.
extensions/ContentTranslation/modules/mw.cx.TargetArticle.js: 222: // {"result":"error","edit":{"spamblacklist":"facebook.com","result":"Failure"}} 223: if ( editResult.spamblacklist ) { 225: mw.msg( 'cx-publish-error-spam-blacklist', editResult.spamblacklist ), 230: // Handle abusefilter errors. 231: if ( editResult.code && editResult.code.indexOf( 'abusefilter' ) === 0 ) { extensions/ContentTranslation/modules/eventlogging/ext.cx.eventlogging.translation.js: 26: mw.hook( 'mw.cx.translation.abusefilter' ).add( this.logAbuseFilter ); 122: var abuseFilterCodes = [ 'abusefilter-warning', 'abusefilter-disallowed' ]; 129: trace.edit.abusefilter 138: trace.edit.abusefilter.id extensions/ContentTranslation/modules/eventlogging/legacy/ext.cx.eventlogging.translation.js: 220: var abuseFilterCodes = [ 'abusefilter-warning', 'abusefilter-disallowed' ]; 227: trace.edit.abusefilter 236: trace.edit.abusefilter.id extensions/ContentTranslation/modules/publish/ext.cx.publish.js: 299: // Handle abusefilter errors. 300: if ( details.edit.code && details.edit.code.indexOf( 'abusefilter' ) === 0 ) { 305: // {"result":"error","edit":{"spamblacklist":"facebook.com","result":"Failure"}} extensions/ContentTranslation/tests/phpunit/AbuseFilterCheckTest.php: 107: [ 'disallow' => [ 'abusefilter-disallow' ] ], 109: 'disallow' => [ 'action' => 'disallow', 'parameters' => [ 'abusefilter-disallow' ] ] 114: [ 'warn' => [ 'abusefilter-warning-cx' ] ], 118: 'parameters' => [ 'abusefilter-warning-cx' ], 119: 'messageHtml' => wfMessage( 'abusefilter-warning-cx' ) 142: [ 'disallow' => [ 'abusefilter-disallow' ], 'degroup' => [] ], 144: 'disallow' => [ 'action' => 'disallow', 'parameters' => [ 'abusefilter-disallow' ] ], 178: [ 'disallow' => [ 'abusefilter-disallow-cx' ] ], 180: 'disallow' => [ 'action' => 'disallow', 'parameters' => [ 'abusefilter-disallow-cx' ] ] 186: [ 'warn' => [ 'abusefilter-warning-cx2' ] ], 190: 'parameters' => [ 'abusefilter-warning-cx2' ], 191: 'messageHtml' => wfMessage( 'abusefilter-warning-cx2' ) 242: [ 'disallow' => [ 'abusefilter-disallow-cx2' ] ],