diff --git a/app/models/application_setting.rb b/app/models/application_setting.rb
index ac6653f5d50..269056e0e77 100644
--- a/app/models/application_setting.rb
+++ b/app/models/application_setting.rb
@@ -71,7 +71,7 @@ class ApplicationSetting < ActiveRecord::Base
             url: true
 
   validates :admin_notification_email,
-            format: { with: Devise.email_regexp },
+            email: true,
             allow_blank: true
 
   validates :two_factor_grace_period,
diff --git a/app/models/email.rb b/app/models/email.rb
index daa259ee2d2..b323d1edd10 100644
--- a/app/models/email.rb
+++ b/app/models/email.rb
@@ -15,7 +15,7 @@ class Email < ActiveRecord::Base
   belongs_to :user
 
   validates :user_id, presence: true
-  validates :email, presence: true, uniqueness: true, format: { with: Devise.email_regexp }
+  validates :email, presence: true, uniqueness: true, email: true
   validate :unique_email, if: ->(email) { email.email_changed? }
 
   before_validation :cleanup_email
diff --git a/app/models/member.rb b/app/models/member.rb
index 0b6785ddbc5..ca08007b7eb 100644
--- a/app/models/member.rb
+++ b/app/models/member.rb
@@ -38,8 +38,7 @@ class Member < ActiveRecord::Base
     presence: {
       if: :invite?
     },
-    format: {
-      with: Devise.email_regexp,
+    email: {
       allow_nil: true
     },
     uniqueness: {
diff --git a/app/models/user.rb b/app/models/user.rb
index edda0ebef86..9fe94b13e52 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -146,8 +146,8 @@ class User < ActiveRecord::Base
   # Validations
   #
   validates :name, presence: true
-  validates :notification_email, presence: true, format: { with: Devise.email_regexp }
-  validates :public_email, presence: true, uniqueness: true, format: { with: Devise.email_regexp }, allow_blank: true
+  validates :notification_email, presence: true, email: true
+  validates :public_email, presence: true, uniqueness: true, email: true, allow_blank: true
   validates :bio, length: { maximum: 255 }, allow_blank: true
   validates :projects_limit, presence: true, numericality: { greater_than_or_equal_to: 0 }
   validates :username,
diff --git a/app/validators/email_validator.rb b/app/validators/email_validator.rb
new file mode 100644
index 00000000000..aab07a7ece4
--- /dev/null
+++ b/app/validators/email_validator.rb
@@ -0,0 +1,5 @@
+class EmailValidator < ActiveModel::EachValidator
+  def validate_each(record, attribute, value)
+    record.errors.add(attribute, :invalid) unless value =~ Devise.email_regexp
+  end
+end