[Plugin: PHPBB Single Sign On] Error 500 when i'm posting on phpBB3

Hello,

The plugin work perfectly but have only one (but very problematic) trouble. If i use the common.php from Single Sign On, I can’t post on my forum (phpBB3, last version), I have an error 500. And if I use the original common.php I can post message but I have an error 500 when I add a user on WordPress. Anyone had this trouble ?

Thanks

https://www.ads-software.com/extend/plugins/phpbb-single-sign-on/