# Troubleshooting
# No communication between ELO Web Client and ELO Web Add-ons
- Make sure the ELO Web Client has loaded after the ELO Web Add-ons program is ready for operation.
- Using the browser console, check whether the ELO Web Client is using both the correct protocol and port.
- You can configure the port used by the ELO Web Client in the profileopts table, while the port for the ELO Web Add-ons program is configured via a registry entry (see above). These settings must match.
- If you have configured HTTPS and are using self-signed certificates, your browser may classify the connection as unsecured. You will recognize this by an error message in the ELO Web Client browser console. In this case, you will have to add the connection in the browser as an exception.
# Error opening the e-mail
With the Send document function, the document is selected and added as an attachment in Microsoft Outlook. If you continue to edit the e-mail, for example, by entering the recipient or changing the subject, in some systems the Unable to open the e-mail error message appears.
- Open the ELO Web Add-ons installation directory.
- Open the Start.cmd file.
- Enter the the following parameter between
"jre\bin\ELO Web Add-ons.exe"and-jar "bin\felix.jar":--add-opens=java.prefs/java.util.prefs=ALL-UNNAMED.