Hello Tahasin!
Thanks for your answer. You are right, my Short-Link works – but it looks different at the WP-Backend than the older ones.
On our Website we have links from our different courses to information-flyer with the hole input our puples need.
The links to the files in our Nextcloud are longer, like: https://bbsapp.bbs-cux.de:5443/index.php/s/waMjAfKCXBkBM5G – you see, no short ones =)
In the past we had no problems with them to put them in an wpdm download. All (old) links are working fine.
But now they won´t save after we ad them.
Du you know the reason for it? Can i change settings or something like that, so it will work even in new or changed wpdm-downloads?