Redmine

I am a new Redmine community member seeking for help.

I installed Redmine 4.2.3 on Ubuntu 20.04 following (https://izolabs.tech/2021/11/install-redmine-on-ubuntu.html). It was successful and I had Redmine working fine without plugins. I followed instruction to install plugins. The first one I tried was redmine_agile-1_6_2-light.zip. It worked! I then installed redmine_dashboard-main.zip and redmine_checklists-3_1_20-light.zip. But my Redmine stopped working. The browser shows the error message same as the picture somene else posted before (https://www.redmine.org/attachments/download/27304/Screenshot%20from%202021-05-02%2023-15-09.png). Uninstallation of the plugins did not recover my Redmine. I then deleted the Redmine folder and reinstalled it. The Redmine worked again. However, the Redmine stopped again after installed the plugin "redmine_agile-1_6_2-light.zip" which had no issue before. Now, no matter what plugin I install, it always kills the freshly installed Redmine.

The /var/log/apache2/error.log displays the following error message:

~_~~~~~~ (Beginning the error message)
......

.......

App 26031 output: /usr/share/passenger/helper-scripts/rack-preloader.rb:29:in `<main>'

[ E 2022-02-02 19:39:51.1268 25833/T1h age/Cor/App/Implementation.cpp:221 ]: Could not spawn process for application /usr/share/redmine: The application encountered the following error: invalid byte sequence in US-ASCII (ArgumentError)

Error ID: 2bf0c873

Error details saved to: /tmp/passenger-error-3gPsRA.html

[ E 2022-02-02 19:39:51.1375 25833/Tc age/Cor/Con/CheckoutSession.cpp:281 ]: [Client 3-1] Cannot checkout session because a spawning error occurred. The identifier of the error is 2bf0c873. Please see earlier logs for details about the error.

~_~~~~~~~~~~~~~~ (end of the error message)

I have been struggling with this issue am terribly frustrated.

Redmine experts, please help! Thank you in advance.