Error 'You are not connected to Salesforce' on ‘Salesforce for Outlook’ side panel

Internet Explorer optimal settings for Salesforce for Outlook

At minimum you need to have your IE configured according to Internet Explorer Settings. The steps below are more application specific, for our client applications.

Before you begin - If you have Salesforce for Outlook (SFO) version 3.0 or later installed, make sure you read our Salesforce for Outlook and TLS article. If you need help figuring out what version, please review Check the version of Salesforce for Outlook.
 

1. Close all Internet Explorer windows and all the programs running. To close SFO, right click on the SFO gray or red icon in the system tray and click on Exit.
2. Bring up the Run command box using the Windows and R key combination. Type in inetcpl.cpl and click on OK.
3. First, we need to reset and restore IE settings. Click on the Advanced tab and click on Restore advanced Settings and then click on Reset.
4. The 'Reset Internet Explorer Settings' will open, check the box for the Delete personal settings, and then click on Reset.
5. Next you would need to click on close.
6. This would close the Internet Options, you need to bring up the Run command box using the Windows and R key combination. Type in inetcpl.cpl and click on OK.
7. On the General tab click the Delete button, and make sure the first box is unchecked, and the following 3 boxes are checked then click Delete - Temporary Internet files and websites files - Cookies and website data - History.
8. Under 'Temporary Internet Files and History Settings,' select the radio button Every time I visit the webpage and set the 'Disk space to use...' to 250.
9. On the Security tab, click on Trusted Sites and click the Sites button.
10. On the 'Trusted sites' window type in https://*.salesforce.com in the 'Add this website to the zone' field. Then click Add, and then click on Close.
11. From the Security tab, click Trusted sites again. Then click on Custom level.  
12. Under Security Settings – Trusted Sites Zone click the Reset to: drop down field and select Low and click Reset. Click on Yes on the warning popup box.
13. Then scroll down in the Setting box on 'Security Settings – Trusted Sites Zone' until you see 'Websites in less privileged web content zone can navigate into this zone' and click on Enable. Also, set the 'Display mixed content' to Enabled and then click on OK.
14. Click on Yes if you get a warning message.
15. Next look for the 'Initialize and script ActiveX controls not marked as safe for scripting' and make sure that the Enable radio button is selected. If it is set to Disabled, the side panel would keep on showing the spinning hour glass in Outlook. Sometimes the main side panel window loads fine but then when you click on compose a new email the side panel window will load and display the 'You're not Connected' message. Note: Please restart the computer and verify the changes sometimes it reverts back. In case if you are not able to modify the IE settings then please get in touch with System administrator. If you set the Custom Level to Low for Trusted site, the value should be set to Enabled automatically but it always helps to verify. Review 'Internet Explorer security levels compared' on Microsoft Support site. 
16. Click on Privacy tab, click on the Sites button and add the domain Salesforce.com in the box and click on Allow.
17. Next, click on the Advanced button in the Privacy tab and check the boxes for Override automatic cookie handling and Always allow session cookies, click on OK.
18. Next and last, click on the Advanced tab. Make sure Allow active content to run in files on My Computer is checked and Check for server certificate revocation* is unchecked.
19. Click on the Connections tab and click on the LAN Settings and make sure none of the boxes are checked, unless there is a proxy server on your network (you would need to check with your IT help desk for more information about this settings). By default the first box Automatically detect settings should be checked. If there are no proxy servers on your network go ahead and uncheck the first box and click on okay * SFO does not support PAC files. Review Recommended settings to run Salesforce in Internet Explorer.
20. Close Internet Options and reopen Internet Explorer.
21. Open Outlook.
22. Open SFO if it's not running in the system tray, then right click on it and click on Settings. On the SFO screen, click on Change User and login again to reset the sync database. Note: Please DO NOT DELETE or RENAME the Sync.db file in the user folder "%appdata%\salesforce.com\Salesforce for Outlook\DB " unless the sync is turned off for all 3 objects (Contacts, Events, and Tasks). 
23. Enter your credentials in the wizard and complete it and then try to reproduce the issue.
24. If the issue still occurs, have your IT try the following: - Create a rule in the Windows Firewall to allow the Sfdcmsol.exe process in Private and Public domain (This is the Salesforce for Outlook application file and it is located in the Salesforce for Outlook folder either in the %localappdata%\Programs\salesforce.com\ or C:\Program Files\salesforce.com\ ) and then restart your computer and try again - Try to set the UAC to Never Notify and restart the computer and try again. See Turn off Windows User Account Control Knowledge article for more information.