Root CA certificate: apachejmetertemporaryrootCA created in JMeter bin directory You can install it following instructions in component reference documentation (see installing the jmeter CA Certificate for HTTPs recording paragraph) Please check the details below when installing the certificate in the browser CN=_DO NOT INSTALL unless this is your certificate (jmeter root CA) OU=username:XXXXXXXXX, C=US Fingerprint(SHA1):XXXXXXXXX Created:XXXXX
If you're talking about this dialog on start of JMeter's proxy:
It is not an error at all. It is about self-signed certificate which is required when you record HTTPS traffic.
If you recording plain HTTP - you can simply ignore this information box.
If you record HTTPS/SSL - you'll need to take an extra step to install ApacheJMeterTemporaryRootCA.crt file (it's being generated in bin folder of your JMeter installation) into your browser.
See Recording HTTPS Traffic with JMeter's Proxy Server guide for more detailed explanation and some troubleshooting tips.