Access To Qlik Sense Fails With Network Load Balancer (NLB)

Access to Qlik Sense Hub fails continuously or intermittently. The deployment has a Network Load Balancer (NLB) between the end-user and the Qlik Sense server. 

Possible symptoms:

• Hub can not be reached
• Connection to Hub breaks intermittently
• HTTP error is displayed instead of Hub content
• Blank page is displayed instead of Hub content

Network Load Balancer (NLB) can be used to balance user load between multiple Qlik Sense Proxy (QPS) nodes. NLB must be configured according to guidance in Network Load Balancer (NLB) With Qlik Sense Enterprise.

Further troubleshooting if problem persists in a properly configured NLB;

• Access QPS directly, without passing through NLB. If this is successful it indicates that Qlik Sense work properly and that NLB is causing the access issue. 
• Confirm that all QPS nodes used by NLB are online and accessible for the affected user. 
• Validate that NLB balancing rule does not include incorrect or missing QPS
• Confirm that hostnames are translated to correct IP, so that DNS resoltuion is not causing the issue
• Audit NLB logs and confirm that user sessions are properly routed to the same QPS through the entire user session

For advice on auditing and validation of NLB configuration and operation, please consult local NLB administrator or NLB vendor for more details. Local IT is often responsible for network equipment, and can assist with equipment configuration and troubleshooting.