Redmine

The internal error page is the result of an unhandled error, that is: an unexpected issues which was not anticipated and thus could not be handled in a more user-friendly way. The error message send to the user in that case is deliberately vague to ensure that no internal settings can be leaked to malicious clients. As a server administrator, you should find more information (including a full error message and a stack trace) in your log/production.log file.

As the the issue itself: it might be you are using MySQL with a column encoding such as utf8 (or well: anything besides utf8mb4). In that case, MySQL can not store 4-Byte unicode characters (such as most emojis or special characters), which might result in an error form the database. If that is the case, see #10772.

In any case, please check your log/production.log file and provide more information. Please see SubmittingBugs for details.

I agree with Holger, most probably is the 4-Byte unicode issue.

In Redmine 4.1 we fixed this problem for new fresh installations (#31921), but for existing installations, before making that change, you need to migrate your database. In that ticket or on all the related issues, you can find various links to articles that describe the process. Please be aware that it's a sensitive process and I highly recommend to backup your data before proceeding.

We can reopen this issue if the logs point to another problem.

Later edit:

I've confirmed that is the 4-Byte unicode problem:

Mysql2::Error: Incorrect string value: '\xE2\x89\xA4 0 ...' for column 'notes' at row 1: INSERT INTO `journals` (`journalized_id`, `journalized_type`, `user_id`, `notes`, `created_on`) VALUES (6, 'Issue', 1, 'Curve Line thickness scaled to absorbance of each individual channel. AL# ≤ 0 = no line, AL# ≥ 4 = maximum line thickness.\r\n\r\n', '2021-01-24 23:40:24')