diff --git a/CHANGELOG b/CHANGELOG
index 8865760217..2e57bdb078 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -13,6 +13,7 @@ v 8.8.3
   - Add Application Setting to configure Container Registry token expire delay (default 5min). !4364
   - Pass the "Remember me" value to the 2FA token form. !4369
   - Fix incorrect links on pipeline page when merge request created from fork.  !4376
+  - Use downcased path to container repository as this is expected path by Docker. !4420
 
 v 8.8.2
   - Added remove due date button. !4209
diff --git a/app/models/project.rb b/app/models/project.rb
index 37de1dfe4d..4e3d92507f 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -309,21 +309,25 @@ class Project < ActiveRecord::Base
     @repository ||= Repository.new(path_with_namespace, self)
   end
 
+  def container_registry_path_with_namespace
+    path_with_namespace.downcase
+  end
+
   def container_registry_repository
     return unless Gitlab.config.registry.enabled
 
     @container_registry_repository ||= begin
-      token = Auth::ContainerRegistryAuthenticationService.full_access_token(path_with_namespace)
+      token = Auth::ContainerRegistryAuthenticationService.full_access_token(container_registry_path_with_namespace)
       url = Gitlab.config.registry.api_url
       host_port = Gitlab.config.registry.host_port
       registry = ContainerRegistry::Registry.new(url, token: token, path: host_port)
-      registry.repository(path_with_namespace)
+      registry.repository(container_registry_path_with_namespace)
     end
   end
 
   def container_registry_repository_url
     if Gitlab.config.registry.enabled
-      "#{Gitlab.config.registry.host_port}/#{path_with_namespace}"
+      "#{Gitlab.config.registry.host_port}/#{container_registry_path_with_namespace}"
     end
   end
 
diff --git a/spec/models/project_spec.rb b/spec/models/project_spec.rb
index 60e1ec43f2..3cabf3aef5 100644
--- a/spec/models/project_spec.rb
+++ b/spec/models/project_spec.rb
@@ -784,6 +784,15 @@ describe Project, models: true do
     end
   end
 
+  describe '#container_registry_path_with_namespace' do
+    let(:project) { create(:empty_project, path: 'PROJECT') }
+
+    subject { project.container_registry_path_with_namespace }
+
+    it { is_expected.not_to eq(project.path_with_namespace) }
+    it { is_expected.to eq(project.path_with_namespace.downcase) }
+  end
+
   describe '#container_registry_repository' do
     let(:project) { create(:empty_project) }