Warning: json_decode() expects parameter 1 to be string

Hello, when I get on the “Edit Profile” site, I get this error:

https://prntscr.com/nw547b

Warning: json_decode() expects parameter 1 to be string, array given in /homepages/29/d733658561/htdocs/clickandbuilds/champlife/wp-content/plugins/user-registration/includes/shortcodes/class-ur-shortcode-my-account.php on line 158

Its this site:
https://champlife.de/mein-konto/edit-profile

Here you can see the line in the webspace:
https://prntscr.com/nw54bu

I hope you can help me. Thank you
Elias