mirror over ssh impossible

I have migrated gitlab to a new server about 2 months ago, and changed from CE to EE when migrating. I had everything working (where some problems with secrets, but we resolved those) when we installed the licence.

That is also the time I enabled git mirroring for a coupe of projects.

The mirroring stopped about a month ago for projects using ssh (private repo's) and we can no longer open de settings > repository page

We get a 500 Error in the browser.

I have also tried creating a new mirror using ssh, I get the 500 as soon as i save.

gitlab-ctl tail gives me following:

Started GET "/odoo/enterprise/settings/repository" for 81.83.18.171 at 2019-03-08 09:20:44 +0000
Processing by Projects::Settings::RepositoryController#show as HTML
  Parameters: {"namespace_id"=>"odoo", "project_id"=>"enterprise"}
Completed 500 Internal Server Error in 219ms (ActiveRecord: 7.7ms | Elasticsearch: 0.0ms)

ActionView::Template::Error (bad decrypt):
    18:
    19: %template.js-pull-mirrors-form
    20:   = f.hidden_field :mirror, value: '1'
    21:   = f.hidden_field :username_only_import_url, class: 'js-mirror-url-hidden', required: true, pattern: "(#{protocols}):\/\/.+"
    22:   = f.hidden_field :only_mirror_protected_branches, class: 'js-mirror-protected-hidden'
    23:
    24:   = f.fields_for :import_data, import_data do |import_form|

app/models/concerns/mirror_authentication.rb:35:in `block in credentials_field'
ee/app/models/ee/project.rb:352:in `username_only_import_url'
ee/app/views/projects/mirrors/_mirror_repos_form.html.haml:21:in `_ee_app_views_projects_mirrors__mirror_repos_form_html_haml___3344055863639225290_70003678989880'
app/views/projects/mirrors/_mirror_repos.html.haml:27:in `block in _app_views_projects_mirrors__mirror_repos_html_haml___1789359892714411875_70003673364840'
app/views/projects/mirrors/_mirror_repos.html.haml:14:in `_app_views_projects_mirrors__mirror_repos_html_haml___1789359892714411875_70003673364840'
app/views/projects/settings/repository/show.html.haml:7:in `_app_views_projects_settings_repository_show_html_haml__650374433448257194_70003665251660'
app/controllers/application_controller.rb:113:in `render'
ee/app/controllers/ee/projects/settings/repository_controller.rb:50:in `render_show'
app/controllers/projects/settings/repository_controller.rb:10:in `show'
lib/gitlab/i18n.rb:55:in `with_locale'
lib/gitlab/i18n.rb:61:in `with_user_locale'
app/controllers/application_controller.rb:423:in `set_locale'
lib/gitlab/middleware/rails_queue_duration.rb:24:in `call'
lib/gitlab/metrics/rack_middleware.rb:17:in `block in call'
lib/gitlab/metrics/transaction.rb:55:in `run'
lib/gitlab/metrics/rack_middleware.rb:17:in `call'
lib/gitlab/middleware/multipart.rb:103:in `call'
lib/gitlab/request_profiler/middleware.rb:16:in `call'
ee/lib/gitlab/jira/middleware.rb:17:in `call'
lib/gitlab/middleware/go.rb:20:in `call'
lib/gitlab/etag_caching/middleware.rb:13:in `call'
lib/gitlab/middleware/correlation_id.rb:16:in `block in call'
lib/gitlab/correlation_id.rb:15:in `use_id'
lib/gitlab/middleware/correlation_id.rb:15:in `call'
lib/gitlab/middleware/read_only/controller.rb:42:in `call'
lib/gitlab/middleware/read_only.rb:18:in `call'
lib/gitlab/middleware/basic_health_check.rb:25:in `call'
lib/gitlab/request_context.rb:20:in `call'
lib/gitlab/metrics/requests_rack_middleware.rb:29:in `call'
lib/gitlab/middleware/release_env.rb:13:in `call'

gitlab-rails console:

-------------------------------------------------------------------------------------
 GitLab:       11.8.1-ee (39d0b2ef98d)
 GitLab Shell: 8.4.4
 postgresql:   9.6.11
-------------------------------------------------------------------------------------
Loading production environment (Rails 5.0.7.1)
irb(main):001:0> p = Project.find_by_full_path('odoo/enterprise')
=> #<Project id:671 odoo/enterprise>
irb(main):002:0> p.username_only_import_url
Traceback (most recent call last):
       16: from bin/rails:4:in `<main>'
       15: from bin/rails:4:in `require'
       14: from /opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/railties-5.0.7.1/lib/rails/commands.rb:18:in `<top (required)>'
       13: from /opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/railties-5.0.7.1/lib/rails/commands/commands_tasks.rb:49:in `run_command!'
       12: from /opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/railties-5.0.7.1/lib/rails/commands/commands_tasks.rb:78:in `console'
       11: from /opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/railties-5.0.7.1/lib/rails/commands/console_helper.rb:9:in `start'
       10: from /opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/railties-5.0.7.1/lib/rails/commands/console.rb:65:in `start'
        9: from (irb):2
        8: from /opt/gitlab/embedded/service/gitlab-rails/ee/app/models/ee/project.rb:352:in `username_only_import_url'
        7: from /opt/gitlab/embedded/service/gitlab-rails/app/models/concerns/mirror_authentication.rb:35:in `block in credentials_field'
        6: from /opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/attr_encrypted-3.1.0/lib/attr_encrypted.rb:161:in `block (2 levels) in attr_encrypted'
        5: from /opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/attr_encrypted-3.1.0/lib/attr_encrypted.rb:329:in `decrypt'
        4: from /opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/attr_encrypted-3.1.0/lib/attr_encrypted.rb:240:in `decrypt'
        3: from /opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/encryptor-3.0.0/lib/encryptor.rb:49:in `decrypt'
        2: from /opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/encryptor-3.0.0/lib/encryptor.rb:98:in `crypt'
        1: from /opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/encryptor-3.0.0/lib/encryptor.rb:98:in `final'
OpenSSL::Cipher::CipherError (bad decrypt)

Edited Mar 08, 2019 by schouteden rod