I have Kpacs Server installed on one PC and running. On another PC I have installed Kpacs and IQ View (because when one was not working I tried the other one). I set up the DICOM settings in all 3 applications, echo works, Win10 on both machines, firewalls off, no AV (except the one integrated in Win10).
When I query the server I get the following log in Kpacs:
7/25/2019 3:51:51 PM ThreadID[0] : C-Find request on STUDY level with KPServer initiated.
*******************************************************
[0] >> : c-Find association with KPServer rejected
*******************************************************
7/25/2019 3:51:51 PM ThreadID[0] : Closed.
Task processed with errors
*******************************************************
and in IQ:
15:58:05.281 [DICOM] Configured a total of 1 presentation contexts for SCU
15:58:05.282 [DICOM] Request Parameters:
====================== BEGIN A-ASSOCIATE-RQ =====================
Our Implementation Class UID: 1.2.826.0.1.3680043.2.360.0
Our Implementation Version Name: IIS_361_20131114
Their Implementation Class UID:
Their Implementation Version Name:
Application Context Name: 1.2.840.10008.3.1.1.1
Calling Application Name: IQView
Called Application Name: KPServer
Responding Application Name: resp. AP Title
Our Max PDU Receive Size: 16384
Their Max PDU Receive Size: 0
Presentation Contexts:
Context ID: 1 (Proposed)
Abstract Syntax: =FINDStudyRootQueryRetrieveInformationModel
Proposed SCP/SCU Role: Default
Proposed Transfer Syntax(es):
=LittleEndianExplicit
=BigEndianExplicit
=LittleEndianImplicit
Requested Extended Negotiation: none
Accepted Extended Negotiation: none
Requested User Identity Negotiation: none
User Identity Negotiation Response: none
======================= END A-ASSOCIATE-RQ ======================
15:58:05.282 [DICOM] Requesting Association
15:58:05.295 [DICOM] Association Parameters Negotiated:
====================== BEGIN A-ASSOCIATE-AC =====================
Our Implementation Class UID: 1.2.826.0.1.3680043.2.360.0
Our Implementation Version Name: IIS_361_20131114
Their Implementation Class UID: 1.2.826.0.1.3680043.2.360.0.3.5.4
Their Implementation Version Name: IIS_354
Application Context Name: 1.2.840.10008.3.1.1.1
Calling Application Name: IQView
Called Application Name: KPServer
Responding Application Name: KPServer
Our Max PDU Receive Size: 16384
Their Max PDU Receive Size: 16384
Presentation Contexts:
Context ID: 1 (Abstract Syntax Not Supported)
Abstract Syntax: =FINDStudyRootQueryRetrieveInformationModel
Proposed SCP/SCU Role: Default
Accepted SCP/SCU Role: Default
Requested Extended Negotiation: none
Accepted Extended Negotiation: none
Requested User Identity Negotiation: none
User Identity Negotiation Response: none
======================= END A-ASSOCIATE-AC ======================
15:58:05.295 [DICOM] No Acceptable Presentation Contexts
15:58:05.296 [DICOM] Unable to negotiate association: No acceptable Presentation Contexts
15:58:05.296 [DICOM] Aborting Association
15:58:05.298 [DICOM] Cleaning up internal association and network structures
What am I missing??? 
Thank you in advance for your help