HPE 1950 vlan setup?

Question

network hardware

There are two HPE 1950s combined in an IRF(stack).
Created about 12 VLANs with subnets like 192.168.31.0/26
When created, a subsequent VLAN is created, but when configuring VLAN Interfaces, it is not important to set a DHCP or Manual address and select any subnet. Even the smallest, an error message is issued. can issue the configuration because
of configuration
conflict

Answer 1

As szelga already said , it can be a matter of limitations.
the datasheet says the following:
Provides basic routing (supporting up to 512 static routes and 32 VLAN interface on
aggregation model; 32 static routes and 8 VLAN interfaces on access models); allows manual
routing configuration
i.e. depending on the model, you have 8 or 32 L3 interfaces.
Are you sure you created 12 pieces? show the whole switch config