I've installed many instances of openproject successufully.

This time I catch thi error ..... Could you help me?

[openproject] ./bin/postinstall
rake aborted!
Psych::SyntaxError: (<unknown>): found character that cannot start any token while scanning for the next token at line 38 column 18
/opt/openproject/lib/open_project/configuration.rb:462:in `load_config_from_file'
/opt/openproject/lib/open_project/configuration.rb:208:in `load'
/opt/openproject/lib/open_project/configuration.rb:276:in `[]'
/opt/openproject/config/application.rb:195:in `<class:Application>'
/opt/openproject/config/application.rb:90:in `<module:OpenProject>'
/opt/openproject/config/application.rb:86:in `<top (required)>'
/opt/openproject/Rakefile:33:in `require'
/opt/openproject/Rakefile:33:in `<top (required)>'
/opt/openproject/vendor/bundle/ruby/2.7.0/gems/rake-13.0.3/exe/rake:27:in `<top (required)>'
/opt/openproject/bin/bundle:110:in `load'
/opt/openproject/bin/bundle:110:in `<main>'

I ran into this exact error. The issue was my SMTP password contained invalid characters for the YAML file it was stored in. Line 38 column 18 is a reference to /opt/openproject/config/configuration.yml, however the actual password is stored elsewhere. To correct the error, I updated my password in /etc/openproject/installer.dat and then ran openproject configure again. I'm running Linux Mint/Ubuntu so there might be some minor path translation needed for Centos.

Hope this helps!

Thanks for your response! 

It was the same for my case: changing @ char in SMTP password solved issue.