Network can't be deleted (already in use)

Hi there,

i’m a total newbie to docker and containers, yet after long hours of searching for the solution myself i had to give up. My hope is to find some help here, even though i’m aware the solution might be embarrasingly easy.

Anyway, i’m running Portainer on my Synology NAS. The portainer-container is running well, and the network is connected to Docker (bridge).
I want to use macvlan, so i created a network Configuration and Creation.
When looking at the network overview i saw that the configuration didn’t show macvlan as driver, while the Creation did so.
I figured i must have done so accidentially, so i deleted both the Configuration as well as the Creation. Creating the configuration new worked well, yet when i create the Creation (funny thing to say) it tells me that the “failed to allocate gateway, address is already in use”.
I also cannot delete the configuration, as it tells me that it already is in use.

The network was never assigned to a container.

I have no idea how i can stop the usage of this network so that i can set it up successfully again. If anyone might have an idea how this can be solved i’d much appreciate it.

Thanks in advance!