Antispam configuration cannot open

Hello,

if i click on the Antispam Plugin, i get this: CB\Plugin\AntiSpam\Captcha::getCaptcha(): Return value must be of type string, null returned
The same comes, when i try to register a new user.

I get the info from users, that thy cannot register to our community. What can i do?

CB: 2.9.2
AntiSpam: 6.0.0+build.2024.05.28.15.24.38.c4b90f999"

Your CB AntiSpam is out of date. There have been 5 releases since your version. Your issue does not appear to exist in latest release.

I recommend resubscribing and updating to latest release. Alternative is to try and fix the plugin yourself or you'll have to unpublish it.