How to fix 500 error in redmine?

Question

Ruby on Rails

Updated Redmine to version 3.3.2. Everything is fine, except that after installing almost any plugin, 500 errors are pouring in (only on the page of the same plugin). I wanted to put a password manager
. Everything was done according to the instructions.
Ruby version: 2.2.6p396
Rails version: 4.2.7.1
Installed plugins: a_common_libs, redmine_issue_tabs, usability.
PS Same thing when installing Agile Plugin.

Answer 1

Problem solved. https://github.com/cantino/huginn/issues/1201

Answer 2

The page https://noshutdown.ru/en/redmine-plugins-vault/#install has information about this.

When set to Redmine 3.* add 
`Rails.application.config.assets.precompile += %w( zeroclipboard.js )` 
to 
`config/initializers/assets.rb` and restart your server.