diff --git a/app/controllers/customers_controller.rb b/app/controllers/customers_controller.rb
index 0a79838..1422efc 100644
--- a/app/controllers/customers_controller.rb
+++ b/app/controllers/customers_controller.rb
@@ -69,7 +69,7 @@ class CustomersController < ApplicationController
   def create
     @customer = Customer.new(allowed_params)
     if @customer.save
-      flash[:notice] = "New Customer Created"
+      flash[:notice] = t :notice_customer_created
       redirect_to @customer
     else
       flash[:error] = @customer.errors.full_messages.to_sentence
@@ -90,6 +90,7 @@ class CustomersController < ApplicationController
       @issues.open.each { |i| @hours+= i.total_spent_hours }
       @closed_issues.each { |i| @closed_hours+= i.total_spent_hours }
     rescue 
+      flash[:error] = t :notice_customer_not_found
       render_404
     end
   end
@@ -99,6 +100,7 @@ class CustomersController < ApplicationController
     begin
       @customer = Customer.find_by_id(params[:id])
     rescue 
+      flash[:error] = t :notice_customer_not_found
       render_404
     end
   end
@@ -108,13 +110,14 @@ class CustomersController < ApplicationController
     begin
       @customer = Customer.find_by_id(params[:id])
       if @customer.update(allowed_params)
-        flash[:notice] = "Customer updated"
+        flash[:notice] = tv :notice_customer_updated
         redirect_to @customer
       else
         redirect_to edit_customer_path
         flash[:error] = @customer.errors.full_messages.to_sentence if @customer.errors
       end
     rescue 
+      flash[:error] = t :notice_customer_not_found
       render_404
     end
   end
@@ -123,9 +126,10 @@ class CustomersController < ApplicationController
   def destroy
     begin
       Customer.find_by_id(params[:id]).destroy
-      flash[:notice] = "Customer deleted successfully"
+      flash[:notice] = t :notice_customer_deleted
       redirect_to action: :index
     rescue 
+      flash[:error] = t :notice_customer_not_deleted
       render_404
     end
   end
@@ -143,6 +147,7 @@ class CustomersController < ApplicationController
       issue = Issue.find_by_id(params[:id])
       redirect_to view_path issue.share_token.token
     rescue
+      flash[:error] = t :notice_issue_not_found
       render_404
     end
   end
@@ -178,6 +183,7 @@ class CustomersController < ApplicationController
       @time_entry = TimeEntry.new(issue: @issue, project: @issue.project)
       @relation = IssueRelation.new
     rescue
+      flash[:error] = t :notice_forbidden
       render_403
     end
   end
diff --git a/app/controllers/estimate_controller.rb b/app/controllers/estimate_controller.rb
index 78e4f00..14ccbec 100644
--- a/app/controllers/estimate_controller.rb
+++ b/app/controllers/estimate_controller.rb
@@ -38,7 +38,7 @@ class EstimateController < ApplicationController
     begin
       send_data estimate.pdf, filename: "estimate #{estimate.doc_number}.pdf", disposition: :inline, type: "application/pdf"
     rescue
-      redirect_to :back, flash: { error: "Estimate not found" }
+      redirect_to :back, flash: { error: I18n.t(:notice_estimate_not_found) }
     end
   end
 
@@ -51,7 +51,7 @@ class EstimateController < ApplicationController
     begin
       send_data estimate.pdf, filename: "estimate #{estimate.doc_number}.pdf", disposition: :inline, type: "application/pdf"
     rescue
-      redirect_to :back, flash: { error: "Estimate not found" }
+      redirect_to :back, flash: { error: I18n.t(:notice_estimate_not_found) }
     end
   end
 
diff --git a/app/controllers/invoice_controller.rb b/app/controllers/invoice_controller.rb
index dc7241b..09a9749 100644
--- a/app/controllers/invoice_controller.rb
+++ b/app/controllers/invoice_controller.rb
@@ -48,7 +48,7 @@ class InvoiceController < ApplicationController
         send_data @pdf, filename: "invoice #{ref}.pdf", disposition: :inline, type: "application/pdf"
       end
     rescue
-      redirect_to :back, flash: { error: "Invoice not found" }
+      redirect_to :back, flash: { error: I18n.t(:notice_invoice_not_found) }
     end
   end
 end
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 0201549..14d9116 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -85,4 +85,17 @@ en:
   label_syncing: "Syncing Quickbooks"
   label_sandbox: "Sandbox"
   button_bulk_pdf: "Bulk PDF"
-  label_select_all: "Select All"
\ No newline at end of file
+  label_select_all: "Select All"
+  notice_customer_created: "Customer created in Quickbooks"
+  notice_customer_updated: "Customer updated in Quickbooks"
+  notice_customer_not_found: "Customer not found in Quickbooks"
+  notice_customer_not_deleted: "Customer could not be deleted in Quickbooks"
+  notice_customer_deleted: "Customer deleted in Quickbooks"
+  notice_estimate_created: "Estimate created in Quickbooks"
+  notice_estimate_updated: "Estimate updated in Quickbooks"
+  notice_estimate_not_found: "Estimate not found"
+  notice_invoice_created: "Invoice created in Quickbooks"
+  notice_invoice_updated: "Invoice updated in Quickbooks"
+  notice_invoice_not_found: "Invoice not found"
+  notice_forbidden: "You do not have permission to access this resource"
+  notice_issue_not_found: "Issue not found"
\ No newline at end of file