Error when changing group permissions

[svherpen]

I'm having a problem when I want to set certain group permissions in jDownloads->Usergroup settings.
It works fine for al the default Joomla categories that are standard (Public, Registered, Supper Admin and so on), but it fails on the groups that I've added myself (like guest and some others).
The message I get is "Checkout failed because of the next error:   "
(Not further error is specified).

Seems like there's something wrong with the synchronization (?) of Joomla groups and jDownloads groups.

Please advise how to fix, as this is kind of important to be setup correct.

I'm running Joomla 3.6.4, jDownloads 3.2.46 and PHP 5.6.27

If needed, I can create a superuser account for you Arno so you can have a look yourself.

Best regards,
Sjaak

[Arno]

Hi,
please send me login data via PM.
I could not reproduce your problem here.