Jenkins 2.5 installation error (An error occurred during installation: Forbidden)

Question

I have a fresh CentOS box, installed Tomcat 8.0 and Jenkins 2.5. After entering the secret key for a brand new installation, the next step Install suggested plugins or :Select plugins to install:. After clicking on Install suggested plugins I got an error saying

An error occurred during installation: Forbidden

I assume is related to folder permissions, the question is which one?

UPDATE: The jenkins log says

Found invalid crumb a711b93261896fb36a1d6ffbe163dca6. Will check remaining parameters for a valid one...
May 21, 2016 4:19:34 AM WARNING hudson.security.csrf.CrumbFilter doFilter No valid crumb was included in request for /jenkins/administrativeMonitor/hudson.diagnosis.ReverseProxySetupMonitor/test. Returning 403.*

Thanks in advance.

Answer 1

If it's any help to anybody, I "fixed it" by restarting Jenkins http://jenkins:8080/restart, or whatever protocol, domain, and port. Then when I went back in it asked me for the secret key again, and then installed all the plugins successfully.

Answer 2

I have faced this problem before. It was because I was using a VPN. Once I closed the VPN, everything returned back to normal.