As soon as DHCP Scope Vendor Option is set devices on HP 1820 get no DHCP offers

Hi,

first of all im no Network admin so if my problem is unclear im sorry in advance.

So we have Unify IP 35G HPA IP Phones on a seperate VLAN. The vendor gave us Scope Options for the Scope(Name,VLAN,DLS Server). These work fine unless the Phone is behind one of our HPE OfficeConnect Switch 1820 8G. As soon as i set the Scope Option the Phones wont renew their lease and cant reconnect - they work fine if they had a lease/reservation before that. Without the Option they work fine.

I would have understood this if it was the other way around(no scope Option - no vlan and no dhcp)

The thing is if the options are not set the autosetup of the phones wont work and i have to do it by hand.

Phones -> HP 1820 -> HP 2530-48G-PoE+-2SFP -> Core

Does anyone have an idea i could try?