500 error on preview

Hello guys I have the same exact problem!
I keep having a 500 error while trying to see previews on my production website.

This is what I do :

  • Make a change in prismic UI for an already published document
  • Click save then the preview button
  • This redirects me to my website on the correct url but it shows the 500 page instead

This does seem to work locally (I've set up a preview to my localhost and this does work perfectly)
The cookie content is as follow :


The only way I found to get rid of the 500 after that is to manually remove the cookies in the application tab.

I've already tried the troubleshooting guide but this didn't help me.

I can provide a copy of my project in private message if needed, thanks for your help

Hi Romain,

I'll be happy to help you debug this. Have you made any changes in your project recently?


Hello Phil :slight_smile:

Yes I've upgraded prismic client to v6 a few days/weeks ago and followed the migration guide but I'm not sure that's where the problem come from

In that case, it's related to this thread: