Problem
When attempting to perform an online search, you get the following error:
Citavi cannot establish a connection with the Citavi server. Please check your Internet connection or try again later.

Cause
Citavi cannot establish a connection with the Citavi server.

Solutions
Check the following items: 

  1. Do you use a proxy server? 
    Especially if you are on a corporate or university network, you might not have a direct connection to the Internet, but instead connect through a proxy server. Ask your system administrator for the settings and enter them under Tools > Options > Search > Proxy settings. If you are on a home network, make sure you select the Do not use a proxy option.
     
  2. Is your proxy compatible with HTTP 1.1?
    Your proxy server might not be compatible with the current version of the HTTP protocol. If you can't connect, under Tools > Options > Search > Proxy settings, try selecting the Compatibility mode for HTTP 1.0 proxies checkbox. Ask your system administrator if necessary.
     
  3. Do you use a firewall?
    If you use a firewall, it might block access for Citavi. Check your firewall settings and make sure Citavi is allowed to connect.
     
  4. Do you use Internet security software?
    If you use Internet filtering software such as G-Data, it might use a content filter that prevents Citavi from connecting. Refer to your content filter's documentation to learn how to allow HTTP traffic from Citavi if it is not listed below.
     
    • Kaspersky Endpoint Security: Add Citavi as a trusted application. Open the main window. Switch to the Settings tab and select Anti-Virus protection in the left frame. In the right frame, in the Exclusions and trusted applications section, click the Settings button. In the Trusted Zone window, click the Trusted applications tab. Click the Add button. In the Path field enter %programfiles(x86)%\Citavi 4\bin\Citavi.exe
    • G-Data's content filtering feature can prevent Citavi from downloading search results. In the G-Data AntiVirusKit click Options > Web/IM and then clear the Process Internet content (HTTP) checkbox.