Error: "Communication with the server failed"

Document ID: 43029
Modified: 06/09/2019


1. Date & Time

Verify if the date, time, and  time zone on your PC are correct.


2. Clear browser cache
  1.  Close your browser

  2. Open the Delete Browser History window by using the key combination CTRL + SHIFT + DEL.
    If the window does not appear click Start > typ 'Control panel > Network and Internet > Internet Options > tab General > Delete browser history.

  3. Here you can select what you want to delete. Make sure Temporary Internet Files and Cookies are selected and Preserve Favorites website data is not selected.

  4. Confirm by clicking Delete.
  5. Log in and try to sign
3. Software and hardware known to interfere with Isabel 6
  1. Check if there are specific security software packages installed (or any other programs that might interfere with Isabel 6) and adapt the configuration if necessary.

  2. Disconnect the Isabel 6 cardreader and reconnect on another USB. Try to login.
    If any other reader than the Isabel 6 cardreader is connected to the computer, disconnect it.
4. Network settings

Check the LAN settings:

  1. Click Start > typ 'Control panel' > Network and Internet > Internet Options > tab Connections
  2. Choose LAN settings > verify if 'Automatically Detect Settings' is disabled.
  3. If 'Use automatic configuration script' is active or if a proxy server is configured in the LAN settings, or if you use a firewall, verify with your IT or system administrator that your proxy and/or firewall are configured correctly.
  4. Click OK to save and close these windows.
  5. Close your browser and try again to login.
5. Reinstall your certificates
  1. Remove all Isabel certificates:
    • From the windows Start Menu, search for certmgr.msc and run this program as administrator.
    • Under Personal > Certificates, delete the Isabel certificate(s) matching your card.
    • Under Intermediate Certification Authorities > Certificates, delete the line(s) Isabel Certification Authority and Isabel Certification Authority Root.
    • Under Trusted Root Certification Authorities > Certificates, delete the line(s) Isabel Certification Authority and Isabel Certification Authority Root.

  2. Reinstall your Isabel certificates:
    • Open the Isabel Control Panel: Start > (All) Programs > Isabel Services > Isabel 6 Control Panel.
    • Double-click 'CA'
    • Double-click on 'Install your Certificate'.
      or click on the following button (only for Internet Explorer):


Start Isabel 6 and try to login.

6. Trusted Sites and Secured connection

Verify if the websites of Isabel 6 and/or eGovernment websites are available in your list of Trusted Sites.

Make sure you have installed the latest security patches in Windows and verify the following settings in Internet Explorer:

  1. Click Start > typ 'Control Panel' > Network and Internet > Internet Options > tab Security.
  2. Click on Trusted sites and set the security level to Medium-Low.
    Disable the option "Enable Portected Mode"
  3. SSL and TLS settings: Internet options > Advanced
    • Scroll down to the Security section and disable the option SSL2.0
      Isabel recommends not to use SSL3.0 (but note that very old webapplications might not function anymore)
    • Enable the option TLS1.2.

If you see that the changes to these options are not taken into account or if you cannot modify these settings, please contact your System Administrator.

7. Remove and install the Isabel security components
  1.  Remove the Isabel 6 Security Components.

  2. Install the latest version of the Isabel 6 Security Components via the download area.
    More information on how to download and install the Isabel 6 Security Components can be found on this page.

  3. Reboot the pc.

  4. Install your certificate via Isabel 6 Control Panel
    Start > All Programs > Isabel Services > Isabel 6 Control Panel > Install your certificate

    or click on the following button (only for Internet Explorer):


8. Reset your browser

Reset your browser.

Verify the Internet Options > Connections > LAN settings. Copy all available information since this is required to connect to the internet.

After the reset of your browser, if you have copied some settings at the beginning of the procedure, you can now go back to LAN settings to restore them.
Verify if 'Automatically detect settings' is disabled.

Try to login to Isabel 6.


If the issue is not solved after performing all previous steps, contact Isabel Customer Care.

  1. Verify that all Mac software updates have been installed.

  2. Make sure you are using a supported browser (Safari, Chrome or Firefox) and that the browser is up-to-date

  3. Try agian in one of the other supported browsers.
Error: "Communication with the server failed"