diff --git a/packages/api/src/postUsersToGroups.ts b/packages/api/src/postUsersToGroups.ts
index 2c8c35a2..a4357b9b 100644
--- a/packages/api/src/postUsersToGroups.ts
+++ b/packages/api/src/postUsersToGroups.ts
@@ -3,7 +3,7 @@ import { PostUsersToGroupsRequest, PostUsersToGroupsResponse } from './types';
 async function postUserToGroups({
   secret,
   groupId,
-}: PostUsersToGroupsRequest): Promise<PostUsersToGroupsResponse | null> {
+}: PostUsersToGroupsRequest): Promise<PostUsersToGroupsResponse | { errors: string[] } | null> {
   try {
     const response = await fetch(`${import.meta.env.VITE_SERVER_URL}/api/users-to-groups`, {
       method: 'POST',
@@ -15,7 +15,11 @@ async function postUserToGroups({
     });
 
     if (!response.ok) {
-      throw new Error(`HTTP Error! Status: ${response.status}`);
+      if (response.status < 500) {
+        const errors = (await response.json()) as { errors: string[] };
+        return errors;
+      }
+      throw new Error(`HTTP error! Status: ${response.status}`);
     }
 
     const group = (await response.json()) as { data: PostUsersToGroupsResponse };
diff --git a/packages/api/src/putUsersToGroups.ts b/packages/api/src/putUsersToGroups.ts
index 6d4984a1..94e3fd08 100644
--- a/packages/api/src/putUsersToGroups.ts
+++ b/packages/api/src/putUsersToGroups.ts
@@ -3,7 +3,7 @@ import { PostUsersToGroupsResponse, PutUsersToGroupsRequest } from './types';
 async function postUsersToGroups({
   groupId,
   userToGroupId,
-}: PutUsersToGroupsRequest): Promise<PostUsersToGroupsResponse | null> {
+}: PutUsersToGroupsRequest): Promise<PostUsersToGroupsResponse | { errors: string[] } | null> {
   try {
     const response = await fetch(
       `${import.meta.env.VITE_SERVER_URL}/api/users-to-groups/${userToGroupId}`,
@@ -18,7 +18,11 @@ async function postUsersToGroups({
     );
 
     if (!response.ok) {
-      throw new Error(`HTTP Error! Status: ${response.status}`);
+      if (response.status < 500) {
+        const errors = (await response.json()) as { errors: string[] };
+        return errors;
+      }
+      throw new Error(`HTTP error! Status: ${response.status}`);
     }
 
     const group = (await response.json()) as { data: PostUsersToGroupsResponse };
diff --git a/packages/berlin/src/pages/Account.tsx b/packages/berlin/src/pages/Account.tsx
index 762e59ca..0c477572 100644
--- a/packages/berlin/src/pages/Account.tsx
+++ b/packages/berlin/src/pages/Account.tsx
@@ -167,7 +167,6 @@ function AccountForm({
   const { mutate: mutateUserData } = useMutation({
     mutationFn: putUser,
     onSuccess: async (body) => {
-      console.log({ body });
       if (!body) {
         return;
       }
@@ -191,6 +190,38 @@ function AccountForm({
     },
   });
 
+  const { mutate: mutatePostUsersToGroups } = useMutation({
+    mutationFn: postUsersToGroups,
+    onSuccess: async (body) => {
+      if (!body) {
+        return;
+      }
+
+      if ('errors' in body) {
+        toast.error(`There was an error: ${body.errors.join(', ')}`);
+        return;
+      }
+
+      await queryClient.invalidateQueries({ queryKey: ['user', user?.id, 'users-to-groups'] });
+    },
+  });
+
+  const { mutate: mutatePutUsersToGroups } = useMutation({
+    mutationFn: putUsersToGroups,
+    onSuccess: async (body) => {
+      if (!body) {
+        return;
+      }
+
+      if ('errors' in body) {
+        toast.error(`There was an error: ${body.errors.join(', ')}`);
+        return;
+      }
+
+      await queryClient.invalidateQueries({ queryKey: ['user', user?.id, 'users-to-groups'] });
+    },
+  });
+
   const {
     control,
     register,
@@ -260,11 +291,11 @@ function AccountForm({
 
       // Create user to group if it doesn't exist
       if (!value.userToGroupId) {
-        await postUsersToGroups({
+        await mutatePostUsersToGroups({
           groupId: value.groupId,
         });
       } else {
-        await putUsersToGroups({
+        await mutatePutUsersToGroups({
           groupId: value.groupId,
           userToGroupId: value.userToGroupId,
         });
diff --git a/packages/berlin/src/pages/PublicGroupRegistration.tsx b/packages/berlin/src/pages/PublicGroupRegistration.tsx
index 314e19fb..47c54042 100644
--- a/packages/berlin/src/pages/PublicGroupRegistration.tsx
+++ b/packages/berlin/src/pages/PublicGroupRegistration.tsx
@@ -97,6 +97,12 @@ function PublicGroupRegistration() {
       if (!body) {
         return;
       }
+
+      if ('errors' in body) {
+        toast.error(body.errors.join(', '));
+        return;
+      }
+
       queryClient.invalidateQueries({ queryKey: ['user', user?.id, 'groups'] });
       toast.success(`Updated ${groupCategoryNameParam} group successfully!`);
     },
diff --git a/packages/berlin/src/pages/SecretGroupRegistration.tsx b/packages/berlin/src/pages/SecretGroupRegistration.tsx
index 0ea9ec6a..1ca6b0c3 100644
--- a/packages/berlin/src/pages/SecretGroupRegistration.tsx
+++ b/packages/berlin/src/pages/SecretGroupRegistration.tsx
@@ -83,6 +83,11 @@ function SecretGroupRegistration() {
       if (!body) {
         return;
       }
+      if ('errors' in body) {
+        toast.error(body.errors[0]);
+        return;
+      }
+
       queryClient.invalidateQueries({ queryKey: ['user', 'groups'] });
       toast.success(`Joined ${groupName} group succesfully!`);
     },