This is not an error, but a warning which allert you're browsing a https site encripted with a self-signed certificate. This is a standard behaviour of all browsers while connecting to any site using a self-signed certificate. The reason for that is to protect you against a kind of attack when you're surfing on a site which pretend to be another.
Since you know the source (cliccking on Advance you should see QlikTech AB), you can decide wheter to trust or not on it.
To avoid this issue you have 3 solutions:
1) Using http instead https. Changing the proxy settings
2) Importing the certificate as Trusted root in your local client
3) Use a certificate released from a public CA instead self-signed certificate