API cannot add nested Subnets in a existing Subnet

[joda666]

ansible@server4:> curl --header 'token: ...' -X POST "https://host/phpipam/api/api/subnets/?subnet=10.10.3.0&mask=24&sectionId=3&masterSubnetId=8&allowRequests=1&pingSubnet=1&discoverSubnet=1&description=10.10.3.0/24" | jq
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 77 100 77 0 0 2054 0 --:--:-- --:--:-- --:--:-- 2081
{
"code": 400,
"success": false,
"message": "Invalid request key id2",
"time": 0.009
}
ansible@server4:> curl --header 'token: ...' -X POST "https://host/phpipam/api/api/subnets/?subnet=10.10.3.0&mask=24&sectionId=3&masterSubnetId=0&allowRequests=1&pingSubnet=1&discoverSubnet=1&description=10.10.3.0/24" | jq
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 140 100 140 0 0 3507 0 --:--:-- --:--:-- --:--:-- 3589
{
"code": 409,
"success": false,
"message": "Subnet 10.10.3.0/24 overlaps with 10.10.0.0/19 (Virtuelle Maschinen) in section IPv4",
"time": 0.008
}
ansible@server4:~>

The overlapping network is the MasterSubnetID 8.

Please correct it. Cannot import many nested subnets.