The preview function in the job publication generates a preview under a link that is only valid for 3 seconds and cannot be called up again afterwards.
To have a preview permanently available, you can create your own preview application portal. This allows you to preview job openings without having to publish the job advertisements on your website. 

Proceed as follows: 

1. Create a "Preview" job publication channel.
2. Create an application portal. 
   • Name*: Preview
   • URL path: Preview
   • Organizational unit*: the matching one
   • Job publication channel*: Preview
   • Layout*: the matching one
   • Languages*: the matching one
   • Enable start page: No 
   • Enable job advertisement: Yes
   • Fixed job advertisement template: No
   • Job advertisement template: What you want to be displayed on your site 
   • Fixed application questionnaire: No
   • Application questionnaire: the matching one 
   • Interface: Off 
   • Enable Google for jobs: No
   • Special characteristic: None 
   • IP policy: If required
3. Save the URL of the job application portal "Preview". You can use this to open all jobs that have been published with the "Preview" publication channel.