[Plugin: NextGEN Gallery] site displays album-tag instead of album

need some help over here, did a sweep on the board here but couldnt find anything suitable to solve my problem.

https://decknews.de/fotos/

an album is supposed to be shown. no updates on the plugin nor on wordpress. the site shows the tag as you can obviously see, but not the album. it did for weeks, just discovered it today. so seeing [album id="2" template="extend"] instead of the gallery is not really satisfying ??

any idea where the problem could be rooted? gallery-admin-panel still shows all pictures, same with the sidebar widget on the frontpage. absolutely no idea what could be the problem as it worked already.

help is appreciated.

thanks in advance

cheers

bj?rn