Configuration problem - Plugin not available in page

[Glanum]

Hello,

I installed your Social Media Streams extension on a TYPO3 v8.7.9. I then followed the configuration instructions provided in the manual: https://docs.typo3.org/typo3cms/extensions/pb_social/Configuration/Index.html.

I’m stuck in step 4 because the extension is not displayed in the 'Contains Plugin' drop-down list of my page.