Redmine

Hello everyone,

I am new to Ruby and Redmine. This error appears when trying to open a project. How can this problem be solved?

Using:
*CentOS Linux release 7.6.1810
*Server version: Apache/2.4.6 (CentOS)
*Redmine v.3.4.9
*ruby-2.3.8
*rails-4.2.11
*mysql Ver 15.1 Distrib 5.5.63-MariaDB, for Linux (x86_64) using readline 5.1