diff --git a/src/api/app/mixins/webui/manage_relationships.rb b/src/api/app/mixins/webui/manage_relationships.rb
index e195d18d2c4..fa5821a9582 100644
--- a/src/api/app/mixins/webui/manage_relationships.rb
+++ b/src/api/app/mixins/webui/manage_relationships.rb
@@ -50,7 +50,7 @@ def remove_role
       main_object.remove_role(load_obj, Role.find_by_title(params[:role]))
       main_object.store
     rescue NotFoundError => e
-      flash[:error] = e.summary
+      flash[:error] = e.to_s
     end
     respond_to do |format|
       format.js { render json: 'ok' }
diff --git a/src/api/spec/cassettes/Projects/behaves_like_user_tab/user_roles/Remove_non_existant_role.yml b/src/api/spec/cassettes/Projects/behaves_like_user_tab/user_roles/Remove_non_existant_role.yml
new file mode 100644
index 00000000000..b86f86aa033
--- /dev/null
+++ b/src/api/spec/cassettes/Projects/behaves_like_user_tab/user_roles/Remove_non_existant_role.yml
@@ -0,0 +1,178 @@
+---
+http_interactions:
+- request:
+    method: get
+    uri: http://backend:5352/build/home:user_tab_user/_result?code=unresolvable&view=status
+    body:
+      encoding: US-ASCII
+      string: ''
+    headers:
+      Accept-Encoding:
+      - gzip;q=1.0,deflate;q=0.6,identity;q=0.3
+      Accept:
+      - "*/*"
+      User-Agent:
+      - Ruby
+  response:
+    status:
+      code: 404
+      message: project 'home user_tab_user' does not exist
+    headers:
+      Content-Type:
+      - text/xml
+      Cache-Control:
+      - no-cache
+      Connection:
+      - close
+      Content-Length:
+      - '164'
+    body:
+      encoding: UTF-8
+      string: |
+        <status code="404">
+          <summary>project 'home:user_tab_user' does not exist</summary>
+          <details>404 project 'home:user_tab_user' does not exist</details>
+        </status>
+    http_version: 
+  recorded_at: Mon, 12 Feb 2018 09:39:17 GMT
+- request:
+    method: get
+    uri: http://backend:5352/source/home:user_tab_user/_keyinfo?donotcreatecert=1&withsslcert=1
+    body:
+      encoding: US-ASCII
+      string: ''
+    headers:
+      Accept-Encoding:
+      - gzip;q=1.0,deflate;q=0.6,identity;q=0.3
+      Accept:
+      - "*/*"
+      User-Agent:
+      - Ruby
+  response:
+    status:
+      code: 200
+      message: OK
+    headers:
+      Content-Type:
+      - text/xml
+      Cache-Control:
+      - no-cache
+      Connection:
+      - close
+      Content-Length:
+      - '12'
+    body:
+      encoding: UTF-8
+      string: "<keyinfo />\n"
+    http_version: 
+  recorded_at: Mon, 12 Feb 2018 09:39:17 GMT
+- request:
+    method: get
+    uri: http://backend:5352/build/home:user_tab_user/_result?view=summary
+    body:
+      encoding: US-ASCII
+      string: ''
+    headers:
+      Content-Type:
+      - text/plain
+      Accept-Encoding:
+      - identity
+      Accept:
+      - "*/*"
+      User-Agent:
+      - Ruby
+  response:
+    status:
+      code: 404
+      message: project 'home user_tab_user' does not exist
+    headers:
+      Content-Type:
+      - text/xml
+      Cache-Control:
+      - no-cache
+      Connection:
+      - close
+      Content-Length:
+      - '164'
+    body:
+      encoding: UTF-8
+      string: |
+        <status code="404">
+          <summary>project 'home:user_tab_user' does not exist</summary>
+          <details>404 project 'home:user_tab_user' does not exist</details>
+        </status>
+    http_version: 
+  recorded_at: Mon, 12 Feb 2018 09:39:17 GMT
+- request:
+    method: get
+    uri: http://backend:5352/build/home:user_tab_user/_result?code=unresolvable&view=status
+    body:
+      encoding: US-ASCII
+      string: ''
+    headers:
+      Accept-Encoding:
+      - gzip;q=1.0,deflate;q=0.6,identity;q=0.3
+      Accept:
+      - "*/*"
+      User-Agent:
+      - Ruby
+  response:
+    status:
+      code: 404
+      message: project 'home user_tab_user' does not exist
+    headers:
+      Content-Type:
+      - text/xml
+      Cache-Control:
+      - no-cache
+      Connection:
+      - close
+      Content-Length:
+      - '164'
+    body:
+      encoding: UTF-8
+      string: |
+        <status code="404">
+          <summary>project 'home:user_tab_user' does not exist</summary>
+          <details>404 project 'home:user_tab_user' does not exist</details>
+        </status>
+    http_version: 
+  recorded_at: Mon, 12 Feb 2018 10:23:56 GMT
+- request:
+    method: get
+    uri: http://backend:5352/build/home:user_tab_user/_result?view=summary
+    body:
+      encoding: US-ASCII
+      string: ''
+    headers:
+      Content-Type:
+      - text/plain
+      Accept-Encoding:
+      - identity
+      Accept:
+      - "*/*"
+      User-Agent:
+      - Ruby
+  response:
+    status:
+      code: 404
+      message: project 'home user_tab_user' does not exist
+    headers:
+      Content-Type:
+      - text/xml
+      Cache-Control:
+      - no-cache
+      Connection:
+      - close
+      Content-Length:
+      - '164'
+    body:
+      encoding: UTF-8
+      string: |
+        <status code="404">
+          <summary>project 'home:user_tab_user' does not exist</summary>
+          <details>404 project 'home:user_tab_user' does not exist</details>
+        </status>
+    http_version: 
+  recorded_at: Mon, 12 Feb 2018 10:23:56 GMT
+recorded_with: VCR 4.0.0