לעברית לחצו כאן
Update: as of 3 May 2019, a new certificate installation software was released, the new software automatically installs the certificate also these Softwares
Explanation of the problem:
Google has 2 backup software from your computer that syncs folders on your computer with the cloud folder. 1) the standard software called "Backup and Sync", 2) the commercial version called "Drive File Stream". (To compare programming see here https://support.google.com/drive/answer/7638428)
These programs use their own security certificates (stored in a local file that updates every session), regardless of what is installed on the computer. Because the material is signed with a NetFree certificate that is not known to these software, they interrupt the unsafe connection.
Solution: Import the NetFree certificate into the software files  according to the following instructions:
Importing the certificate
Download the patch software from here, and run it (for Drive File Stream the patch software must be run as administrator - right click > run as administrator).
After the operation is complete, the backup software must be restarted (Click on the icon in the taskbar, click the three dots and choose "Close", then reopen the program, or restart the computer).
Please note! This copies the certificates installed on your computer (not necessarily NetFree) to the certificate file that the software uses, therefore this patch works only if Security certificate has been installed properly! In case of doubt or problem, repeat the the installation of the Security certificate step and then try to run the software in the attachment above.
For drive file stream see https://support.google.com/a/answer/7644837
- Please note that the Drive File Stream software works only partially even after importing the certificate (It downloads files, but updates or additions from the computer to the server does not work, only on very small files - smaller than 50 KB)