Redmine

I can reproduce the problem. "Internal server error" appears after attempting to create a ticket with the following string in the title and description (copied together with the smiley from the google document in comment 1:

A druhá věc, možná bych ten pruh dole, světle modrou, vyměnil za naší tmavě modrou

My version of Redmine:

Environment:
  Redmine version                3.2.4.stable
  Ruby version                   2.0.0-p384 (2014-01-12) [x86_64-linux-gnu]
  Rails version                  4.2.7.1
  Environment                    production
  Database adapter               Mysql2
SCM:
  Subversion                     1.8.8
  Git                            1.9.1
  Filesystem                     
Redmine plugins:
  advanced_roadmap_v2            2.4.2

The are multiple issue reported on the same subject, please see #21398, #18866 and #19742.

We had the same issue and we fixed it by migrating our Mysql database to utf8mb4. I think that the installation doc from RedmineInstall could be improved and include this change.

Update: the smiley in my previous comment was first visible, but now it disappeared.