If you want to get nice block pages on https sites, you need to deploy the Cisco Root CA to your computers. There's much more information at OpenDNS, plus info on deploying via GPO: https://support.opendns.com/hc/en-us/articles/227987007-Block-Page-Errors-Installing-the-Cisco-Root-CA

Here's how to do it with LabTech

Deploy the Cisco Umbrella Certificate

  1. It's a 7z self extracting installer. Feel free to crack it open and look, it's all clean.
  2. Upload that exe to your LT share under /Transfer/Tools/Cert/
  3. Import this script. All it does is download the exe, run it, and delete it.
  4. Install Cisco Umbrella Root Certificate.xml
    <LabTech_Expansion
    	Version="110.349"
    	Name="LabTech Script Expansion"
    	Type="PackedScript">
    	<PackedScript>
    		<NewDataSet>
    			<Table>
    				<ScriptId>6150</ScriptId>
    				<FolderId>219</FolderId>
    				<ScriptName>Install Cisco Umbrella Root Certificate</ScriptName>
    				<ScriptNotes>Get urc_cert from
    https://mega.nz/#!XAMz2SRJ!l6OTbKGz_ieRpsvDGwVidM0v3KdCaxFyXs3cI4wx4_g
     
    it automatically extracts and installs the Cisco Umbrella root cert for IE, Chrome &amp; FF. It will install into every FF profile, including defaults.</ScriptNotes>
    				<Permission>0,</Permission>
    				<EditPermission>0,</EditPermission>
    				<ComputerScript>1</ComputerScript>
    				<LocationScript>0</LocationScript>
    				<MaintenanceScript>0</MaintenanceScript>
    				<FunctionScript>0</FunctionScript>
    				<LicenseData>H4sIAAAAAAAEAFWPTQrCMBSE94J3yAEa8tPY0vIIiIogutHiPk1fMZu0pA3Y20uLQl0NM8M3MHB1Fv2ARzMaDdXUoxbAFoV79Icu+hGD5sBWDk7v3oWZQV29YhgaMyXkYnw0YSIyS4jkIid5qXalUmR/A7Yi4GGD68cnhsF1fp7+D779ObpGF5KnslE1xbSwVAjMaFHzgnKJpk1rI61sf/wCAFsf2m4+z6m76+AAAAA=</LicenseData>
    				<ScriptData>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</ScriptData>
    				<ScriptVersion>1</ScriptVersion>
    				<ScriptGuid>92032d4b-e39c-11e6-9b09-02eaf3ba2c2f</ScriptGuid>
    				<ScriptFlags>0</ScriptFlags>
    				<Parameters></Parameters>
    			</Table>
    		</NewDataSet>
    		<ScriptFolder>
    			<NewDataSet>
    				<Table>
    					<FolderID>219</FolderID>
    					<ParentID>0</ParentID>
    					<Name>OpenDNS</Name>
    					<GUID>a2b8d066-41be-4339-84b6-4dcd83a3add0</GUID>
    				</Table>
    			</NewDataSet>
    		</ScriptFolder>
    	</PackedScript>
    </LabTech_Expansion>

If you can't import, this is what the script looks like