fixes

src/categories/components/CategoryUpdatePage/CategoryUpdatePage.tsx

@@ -178,6 +178,7 @@ export const CategoryUpdatePage: React.FC<CategoryUpdatePageProps> = ({
                 defaultMessage:
                   "Add search engine title and description to make this category easier to find"
               })}
+              errors={errors}
               title={data.seoTitle}
               titlePlaceholder={data.name}
               description={data.seoDescription}

src/collections/components/CollectionDetailsPage/CollectionDetailsPage.tsx

@@ -151,6 +151,7 @@ const CollectionDetailsPage: React.FC<CollectionDetailsPageProps> = ({
                     defaultMessage:
                       "Add search engine title and description to make this collection easier to find"
                   })}
+                  errors={errors}
                   slug={data.slug}
                   slugPlaceholder={data.name}
                   title={data.seoTitle}

src/utils/errors/page.ts

@@ -1,10 +1,16 @@
 import { PageErrorFragment } from "@saleor/fragments/types/PageErrorFragment";
 import { commonMessages } from "@saleor/intl";
 import { PageErrorCode } from "@saleor/types/globalTypes";
-import { IntlShape } from "react-intl";
+import { defineMessages, IntlShape } from "react-intl";
 
 import commonErrorMessages from "./common";
 
+const messages = defineMessages({
+  nameAlreadyTaken: {
+    defaultMessage: "This name is already taken. Please provide another."
+  }
+});
+
 function getPageErrorMessage(
   err: Omit<PageErrorFragment, "__typename"> | undefined,
   intl: IntlShape
@@ -17,6 +23,8 @@ function getPageErrorMessage(
         return intl.formatMessage(commonMessages.requiredField);
       case PageErrorCode.INVALID:
         return intl.formatMessage(commonErrorMessages.invalid);
+      case PageErrorCode.UNIQUE:
+        return intl.formatMessage(messages.nameAlreadyTaken);
       default:
         return intl.formatMessage(commonErrorMessages.unknownError);
     }