It looks like Webroot is no longer supporting OSX El Capitan. You could try to uninstall and reinstall Webroot to see if it will work. OSX El Capitan is no longer supported by Apple since October 2019, are you able to upgrade to something newer such as Sierra, High Sierra or Mojave? If you can let us know you Mac’s model number by doing the following we can determine which version of OSX you can upgrade to.
1. Click the Apple icon in the top left corner of your Mac.
2. This will bring up a drop-down menu. Pick the top option: About This Mac.
3. Click on System Report (or on Macs running older operating systems, click on More Information).
4. In the Hardware Overview you will see the Model Identifier.