diff --git a/apps/admin/.env.example b/apps/admin/.env.example
index a852574..41eae41 100644
--- a/apps/admin/.env.example
+++ b/apps/admin/.env.example
@@ -14,6 +14,10 @@ RESEND_API_KEY=re_your_resend_api_key_here
 EMAIL_FROM=FitAI <noreply@yourdomain.com>
 EMAIL_REPLY_TO=support@yourdomain.com
 
+# Admin App URL (for invitation redirects)
+# Set to your production URL in production
+NEXT_PUBLIC_APP_URL=http://localhost:3000
+
 # Database (optional - defaults to ./fitai.db)
 DATABASE_PATH=./fitai.db
 
diff --git a/apps/admin/data/fitai.db b/apps/admin/data/fitai.db
index f5a3cd0..ed0cb0c 100644
Binary files a/apps/admin/data/fitai.db and b/apps/admin/data/fitai.db differ
diff --git a/apps/admin/src/app/api/users/create/route.ts b/apps/admin/src/app/api/users/create/route.ts
index fe2152d..1ab24bb 100644
--- a/apps/admin/src/app/api/users/create/route.ts
+++ b/apps/admin/src/app/api/users/create/route.ts
@@ -84,12 +84,30 @@ export async function POST(request: NextRequest) {
     if (data.sendInvitation && data.email) {
       try {
         const client = await clerkClient();
+
+        // Build publicMetadata - only include gymId if it exists
+        const publicMetadata: Record<string, any> = {
+          role: data.role,
+        };
+        if (assignedGymId) {
+          publicMetadata.gymId = assignedGymId;
+        }
+
+        // Determine redirect URL based on role
+        // Staff (admin, trainer, superAdmin) → Admin web app
+        // Clients → Mobile app (handled by Clerk's default)
+        const isStaffRole = ["admin", "trainer", "superAdmin"].includes(
+          data.role,
+        );
+        const redirectUrl = isStaffRole
+          ? `${process.env.NEXT_PUBLIC_APP_URL || "http://localhost:3000"}/sign-up`
+          : undefined; // Clients use default Clerk redirect
+
         const invitation = await client.invitations.createInvitation({
           emailAddress: data.email,
-          publicMetadata: {
-            role: data.role,
-            gymId: assignedGymId,
-          },
+          publicMetadata,
+          redirectUrl,
+          ignoreExisting: true, // Don't fail if invitation already exists
         });
 
         log.info("Clerk invitation sent", {
@@ -97,6 +115,7 @@ export async function POST(request: NextRequest) {
           role: data.role,
           gymId: assignedGymId,
           invitationId: invitation.id,
+          redirectUrl: redirectUrl || "default (mobile app)",
         });
 
         // Send custom invitation email (in addition to Clerk's)
@@ -117,7 +136,22 @@ export async function POST(request: NextRequest) {
       } catch (error: unknown) {
         const errorMessage =
           error instanceof Error ? error.message : "Unknown error";
-        log.error("Failed to send Clerk invitation", error);
+
+        // Extract Clerk-specific error details
+        const clerkError = error as any;
+
+        log.error("Failed to send Clerk invitation", error, {
+          email: data.email,
+          role: data.role,
+          gymId: assignedGymId,
+          publicMetadata: assignedGymId
+            ? { role: data.role, gymId: assignedGymId }
+            : { role: data.role },
+          clerkStatus: clerkError?.status,
+          clerkErrors: clerkError?.errors,
+          clerkTraceId: clerkError?.clerkTraceId,
+        });
+
         return errorResponse(`Failed to send invitation: ${errorMessage}`, {
           status: 500,
         });
diff --git a/apps/admin/src/app/api/users/route.ts b/apps/admin/src/app/api/users/route.ts
index a4a2662..298189f 100644
--- a/apps/admin/src/app/api/users/route.ts
+++ b/apps/admin/src/app/api/users/route.ts
@@ -414,14 +414,15 @@ export async function PUT(request: NextRequest) {
       return forbiddenResponse(`Not authorized to assign role '${role}'`);
     }
 
-    // Authorization: trainers cannot reassign users to different gyms
+    // Authorization: trainers and admins cannot reassign users to different gyms
+    // Only superAdmins can reassign gyms
     if (
-      requesterRole === "trainer" &&
+      requesterRole !== "superAdmin" &&
       gymId !== undefined &&
       gymId !== existingUser.gymId
     ) {
       return forbiddenResponse(
-        "Trainers cannot reassign users to different gyms",
+        "Only superAdmins can reassign users to different gyms",
       );
     }
 
diff --git a/apps/admin/src/components/users/UserManagement.tsx b/apps/admin/src/components/users/UserManagement.tsx
index a9c2a32..cd1b983 100644
--- a/apps/admin/src/components/users/UserManagement.tsx
+++ b/apps/admin/src/components/users/UserManagement.tsx
@@ -362,8 +362,12 @@ export function UserManagement({ gymId }: UserManagementProps) {
                 />
               </div>
 
-              {/* Only superAdmins and admins can reassign gyms */}
-              {user?.publicMetadata?.role !== "trainer" && (
+              {/* Only superAdmins can reassign gyms */}
+              {(() => {
+                const currentRole = user?.publicMetadata?.role;
+                console.log("Current user role for gym selector:", currentRole);
+                return currentRole === "superAdmin";
+              })() && (
                 <div className="mb-4">
                   <label className="block text-sm font-medium mb-1">Gym</label>
                   <select
diff --git a/apps/admin/src/lib/validation/schemas.ts b/apps/admin/src/lib/validation/schemas.ts
index f0cdb89..2e15b74 100644
--- a/apps/admin/src/lib/validation/schemas.ts
+++ b/apps/admin/src/lib/validation/schemas.ts
@@ -16,9 +16,12 @@ export const passwordSchema = z
 export const phoneSchema = z
   .string()
   .optional()
-  .refine((val) => !val || /^\+?[1-9]\d{1,14}$/.test(val), {
-    message: "Invalid phone number format",
-  });
+  .refine(
+    (val) => !val || val.trim() === "" || /^\+?[1-9]\d{1,14}$/.test(val),
+    {
+      message: "Invalid phone number format",
+    },
+  );
 
 export const dateTimeSchema = z.string().datetime("Invalid datetime format");