Please provide the Fiddler log files so that we could investigate further.
Meanwhile, verify that you have explicitly accepted the root certificate by focusing and pressing the Windows prompt (which should appear underneath Fiddler Everywhere once your press the Trust Root Certificate button).
Alternatively, you could export and add the certificate manually using the Advanced Settings (Export certificate and then manually add it to your OS certificate store).
when i try to trust root certificate it will say this Unable to trust the root certificate. The operation was cancelled.