I have downloaded (forge-1.12.2-14.23.5.2768-universal.jar) which is the latest version and I have the most recent update of Java installed (jre-8u251-macosx-x64.dmg) directly from their website. I have researched this extensively and would really appreciate some help. When I try to open the forge installer with Jar Launcher my system seems to show me a message that says "The Java JAR file "forge-1.12.2-14.23.5.2768-universal.jar" could not be launched. Check the console for possible error messages. I'm very new to this so please bear with me, this all I've found in the console:
assessment denied for forge-1.12.2-14.23.5.2768-universal.jar
com.apple.message.domain: com.apple.security.assessment.outcome2
com.apple.message.signature2: bundle:UNBUNDLED
com.apple.message.signature4: 3
com.apple.message.signature3: forge-1.12.2-14.23.5.2768-universal.jar
com.apple.message.signature5: UNKNOWN
com.apple.message.signature: denied:no usable signature
SenderMachUUID: 58DD8703-DA55-3642-BD3E-F73AB302F3EA