/var/www/vhosts/daniela-styger.ch/httpdocs/views/category-detail.jade:6 4| div.bg02(style="overflow:hidden;") 5| .container-title > 6| h1(style="margin:0;") #{category.title} 7| block content 8| .container-text 9| each album in albums Cannot read property 'title' of null

TypeError: /var/www/vhosts/daniela-styger.ch/httpdocs/views/category-detail.jade:6
    4| 	div.bg02(style="overflow:hidden;")
    5| 		.container-title
  > 6| 			h1(style="margin:0;") #{category.title}
    7| block content
    8| 	.container-text
    9| 		each album in albums

Cannot read property 'title' of null
    at eval (eval at <anonymous> (/var/www/vhosts/daniela-styger.ch/httpdocs/node_modules/jade/lib/jade.js:152:8), <anonymous>:443:51)
    at /var/www/vhosts/daniela-styger.ch/httpdocs/node_modules/jade/lib/jade.js:153:35
    at Object.exports.render (/var/www/vhosts/daniela-styger.ch/httpdocs/node_modules/jade/lib/jade.js:197:10)
    at Object.exports.renderFile (/var/www/vhosts/daniela-styger.ch/httpdocs/node_modules/jade/lib/jade.js:233:18)
    at View.exports.renderFile [as engine] (/var/www/vhosts/daniela-styger.ch/httpdocs/node_modules/jade/lib/jade.js:218:21)
    at View.render (/var/www/vhosts/daniela-styger.ch/httpdocs/node_modules/express/lib/view.js:76:8)
    at Function.app.render (/var/www/vhosts/daniela-styger.ch/httpdocs/node_modules/express/lib/application.js:504:10)
    at ServerResponse.res.render (/var/www/vhosts/daniela-styger.ch/httpdocs/node_modules/express/lib/response.js:798:7)
    at /var/www/vhosts/daniela-styger.ch/httpdocs/routes/index.js:76:21
    at Query.<anonymous> (/var/www/vhosts/daniela-styger.ch/httpdocs/node_modules/mongoose/lib/model.js:3407:16)
    at /var/www/vhosts/daniela-styger.ch/httpdocs/node_modules/mongoose/node_modules/kareem/index.js:259:21
    at /var/www/vhosts/daniela-styger.ch/httpdocs/node_modules/mongoose/node_modules/kareem/index.js:127:16
    at nextTickCallbackWith0Args (node.js:420:9)
    at process._tickCallback (node.js:349:13)