I can upload a picture without any problems as an admin of the site.

But when the user wants to upload a picture this happens:
After submitting they are sent to a page with the failure text saying:

” Warning: Undefined variable $reply_author_id in /customers/c/d/0/sanvigs-kunstskole.dk/httpd.www/wp-content/plugins/bbpress-notification/bbpress-notification.php on line 377 Warning: Cannot modify header information – headers already sent by (output started at /customers/c/d/0/sanvigs-kunstskole.dk/httpd.www/wp-content/plugins/bbpress-notification/bbpress-notification.php:377) in /customers/c/d/0/sanvigs-kunstskole.dk/httpd.www/wp-includes/pluggable.php on line 1340 Warning: Cannot modify header information – headers already sent by (output started at /customers/c/d/0/sanvigs-kunstskole.dk/httpd.www/wp-content/plugins/bbpress-notification/bbpress-notification.php:377) in /customers/c/d/0/sanvigs-kunstskole.dk/httpd.www/wp-includes/pluggable.php on line 1343 ”

If the user then goes one page back, and is on the forum page where the image should be (still not showing as uploaded) and refresh the page, then the picture is there.
Very strange.

Just to underline. I have tried deactivating all other plugins, but it still happens and my web supporter cant solve it either.

What to do???

[@robin-w Moderator 3 years, 4 months ago]

This is an issue with the bbpress-notification plugin not bbpress, suggest you post to their support forum