IE error "The proxy server is not responding"

[II/JG54_Emil]

Since this week, my Internet Explorer 10.0.9200.16897v isn´t connecting to the internet anymore, while Firefox is working fine.
When when switching to IE-Tab I have the same error-message as in IE.

Der Proxyserver reagiert nicht

•Überprüfen Sie unter „Extras“ > „Internetoptionen“ > „Verbindungen“ Ihre Proxyeinstellungen. Klicken Sie auf „LAN-Einstellungen“, falls Sie sich in einem LAN befinden.
•Vergewissern Sie sich, dass Ihr Webzugriff nicht durch Ihre Firewalleinstellungen blockiert wird.
•Bitten Sie Ihren Systemadministrator um Hilfe.

Google-English:

The proxy server is not responding

• Check under "Tools"> "Internet Options"> "Connections" your proxy settings. Click on "LAN Settings" if you are in a LAN.
• Make sure that your web access is not blocked by your firewall settings.
• Ask your system administrator for assistance.

Did anyone have the same?
What and how can I do to solve this nonsense?

[PA-Dore]

I had the same issue last week (same message): I had installed Skype and I didn"t seen that Skype had installed another security software (I don't remember the name).

I removed it and then all works fine...

[II/JG54_Emil]

Thnak you Pa-Dore this helped me solve the problem.

You´re great!