diff --git a/modules/identity/src/Volo.Abp.Identity.AspNetCore/Volo/Abp/Identity/AspNetCore/AbpSignInManager.cs b/modules/identity/src/Volo.Abp.Identity.AspNetCore/Volo/Abp/Identity/AspNetCore/AbpSignInManager.cs
index 66c57f4c39..dc305c819c 100644
--- a/modules/identity/src/Volo.Abp.Identity.AspNetCore/Volo/Abp/Identity/AspNetCore/AbpSignInManager.cs
+++ b/modules/identity/src/Volo.Abp.Identity.AspNetCore/Volo/Abp/Identity/AspNetCore/AbpSignInManager.cs
@@ -91,6 +91,22 @@ public class AbpSignInManager : SignInManager<IdentityUser>
         return await PasswordSignInAsync(user, password, isPersistent, lockoutOnFailure);
     }
 
+    public override async Task<SignInResult> ExternalLoginSignInAsync(string loginProvider, string providerKey, bool isPersistent, bool bypassTwoFactor)
+    {
+        var user = await FindByLoginAsync(loginProvider, providerKey);
+        if (user == null)
+        {
+            return SignInResult.Failed;
+        }
+
+        var error = await PreSignInCheck(user);
+        if (error != null)
+        {
+            return error;
+        }
+        return await SignInOrTwoFactorAsync(user, isPersistent, loginProvider, bypassTwoFactor);
+    }
+
     public virtual async Task<IdentityUser> FindByEmaiAsync(string email)
     {
         return await _identityUserManager.FindByEmailInHostAsync(email);
@@ -101,6 +117,11 @@ public class AbpSignInManager : SignInManager<IdentityUser>
         return await _identityUserManager.FindByNameInHostAsync(userName);
     }
 
+    public virtual async Task<IdentityUser> FindByLoginAsync(string loginProvider, string providerKey)
+    {
+        return await _identityUserManager.FindByLoginInHostAsync(loginProvider, providerKey);
+    }
+
     /// <summary>
     /// This is to call the protection method PreSignInCheck
     /// </summary>
diff --git a/modules/identity/src/Volo.Abp.Identity.Domain/Volo/Abp/Identity/AbpIdentityUserValidator.cs b/modules/identity/src/Volo.Abp.Identity.Domain/Volo/Abp/Identity/AbpIdentityUserValidator.cs
index 2cce94a57f..5dc6225761 100644
--- a/modules/identity/src/Volo.Abp.Identity.Domain/Volo/Abp/Identity/AbpIdentityUserValidator.cs
+++ b/modules/identity/src/Volo.Abp.Identity.Domain/Volo/Abp/Identity/AbpIdentityUserValidator.cs
@@ -170,10 +170,15 @@ namespace Volo.Abp.Identity
             }
             else
             {
-                var owner = await manager.FindByNameAsync(userName);
+                IdentityUser owner;
+                using (CurrentTenant.Change(user.TenantId))
+                {
+                    owner = await manager.FindByNameAsync(userName);
+                }
                 if (owner != null &&
                     !string.Equals(await manager.GetUserIdAsync(owner), await manager.GetUserIdAsync(user)) &&
-                    owner.TenantId == user.TenantId)
+                    owner.TenantId == user.TenantId &&
+                    owner.NormalizedUserName != manager.NormalizeName(userName))
                 {
                     errors.Add(ErrorDescriber.DuplicateUserName(userName));
                 }
@@ -197,10 +202,15 @@ namespace Volo.Abp.Identity
                 errors.Add(ErrorDescriber.InvalidEmail(email));
                 return errors;
             }
-            var owner = await manager.FindByEmailAsync(email);
+            IdentityUser owner;
+            using (CurrentTenant.Change(user.TenantId))
+            {
+                owner = await manager.FindByEmailAsync(email);
+            }
             if (owner != null &&
                 !string.Equals(await manager.GetUserIdAsync(owner), await manager.GetUserIdAsync(user)) &&
-                owner.TenantId == user.TenantId)
+                owner.TenantId == user.TenantId &&
+                owner.NormalizedEmail != manager.NormalizeEmail(email))
             {
                 errors.Add(ErrorDescriber.DuplicateEmail(email));
             }
diff --git a/modules/identity/src/Volo.Abp.Identity.Domain/Volo/Abp/Identity/IIdentityUserRepository.cs b/modules/identity/src/Volo.Abp.Identity.Domain/Volo/Abp/Identity/IIdentityUserRepository.cs
index d92717c44c..9b7b86f8d4 100644
--- a/modules/identity/src/Volo.Abp.Identity.Domain/Volo/Abp/Identity/IIdentityUserRepository.cs
+++ b/modules/identity/src/Volo.Abp.Identity.Domain/Volo/Abp/Identity/IIdentityUserRepository.cs
@@ -190,6 +190,13 @@ public interface IIdentityUserRepository : IBasicRepository<IdentityUser, Guid>
         CancellationToken cancellationToken = default
     );
 
+    Task<List<IdentityUser>> GetUsersByLoginAsync(
+        [NotNull] string loginProvider,
+        [NotNull] string providerKey,
+        bool includeDetails = false,
+        CancellationToken cancellationToken = default
+    );
+
     Task<IdentityUser> FindByNormalizedUserNameAsync(
         Guid? tenantId,
         [NotNull] string normalizedUserName,
diff --git a/modules/identity/src/Volo.Abp.Identity.Domain/Volo/Abp/Identity/IdentityUserManager.cs b/modules/identity/src/Volo.Abp.Identity.Domain/Volo/Abp/Identity/IdentityUserManager.cs
index 8cd76acd0e..a893bcf530 100644
--- a/modules/identity/src/Volo.Abp.Identity.Domain/Volo/Abp/Identity/IdentityUserManager.cs
+++ b/modules/identity/src/Volo.Abp.Identity.Domain/Volo/Abp/Identity/IdentityUserManager.cs
@@ -657,4 +657,34 @@ public class IdentityUserManager : UserManager<IdentityUser>, IDomainService
             }
         }
     }
+
+    public virtual async Task<IdentityUser> FindByLoginInHostAsync(string loginProvider, string providerKey)
+    {
+        if (MultiTenancyOptions.Value.UserSharingStrategy == TenantUserSharingStrategy.Isolated)
+        {
+            return await base.FindByLoginAsync(loginProvider, providerKey);
+        }
+
+        using (CurrentTenant.Change(null))
+        {
+            using (DataFilter.Disable<IMultiTenant>())
+            {
+                var hostusers = await UserRepository.GetUsersByLoginAsync(loginProvider, providerKey, cancellationToken: CancellationToken);
+                //host user first
+                var hostUser = hostusers.FirstOrDefault(x => x.TenantId == null) ?? hostusers.FirstOrDefault();
+                if (hostUser == null)
+                {
+                    return null;
+                }
+
+                using (DataFilter.Enable<IMultiTenant>())
+                {
+                    using (CurrentTenant.Change(hostUser.TenantId))
+                    {
+                        return await base.FindByLoginAsync(loginProvider, providerKey);
+                    }
+                }
+            }
+        }
+    }
 }
diff --git a/modules/identity/src/Volo.Abp.Identity.EntityFrameworkCore/Volo/Abp/Identity/EntityFrameworkCore/EfCoreIdentityUserRepository.cs b/modules/identity/src/Volo.Abp.Identity.EntityFrameworkCore/Volo/Abp/Identity/EntityFrameworkCore/EfCoreIdentityUserRepository.cs
index 459a73593c..e472448fc9 100644
--- a/modules/identity/src/Volo.Abp.Identity.EntityFrameworkCore/Volo/Abp/Identity/EntityFrameworkCore/EfCoreIdentityUserRepository.cs
+++ b/modules/identity/src/Volo.Abp.Identity.EntityFrameworkCore/Volo/Abp/Identity/EntityFrameworkCore/EfCoreIdentityUserRepository.cs
@@ -493,6 +493,15 @@ public class EfCoreIdentityUserRepository : EfCoreRepository<IIdentityDbContext,
             .ToListAsync(GetCancellationToken(cancellationToken));
     }
 
+    public virtual async Task<List<IdentityUser>> GetUsersByLoginAsync(string loginProvider, string providerKey, bool includeDetails = false, CancellationToken cancellationToken = default)
+    {
+        return await (await GetDbSetAsync())
+            .IncludeDetails(includeDetails)
+            .OrderBy(x => x.Id)
+            .Where(u => u.Logins.Any(login => login.LoginProvider == loginProvider && login.ProviderKey == providerKey))
+            .ToListAsync(GetCancellationToken(cancellationToken));
+    }
+
     public virtual async Task<IdentityUser> FindByNormalizedUserNameAsync(Guid? tenantId, string normalizedUserName, bool includeDetails = true, CancellationToken cancellationToken = default)
     {
         return await (await GetDbSetAsync())
diff --git a/modules/identity/src/Volo.Abp.Identity.MongoDB/Volo/Abp/Identity/MongoDB/MongoIdentityUserRepository.cs b/modules/identity/src/Volo.Abp.Identity.MongoDB/Volo/Abp/Identity/MongoDB/MongoIdentityUserRepository.cs
index 718d461b87..c2c23344eb 100644
--- a/modules/identity/src/Volo.Abp.Identity.MongoDB/Volo/Abp/Identity/MongoDB/MongoIdentityUserRepository.cs
+++ b/modules/identity/src/Volo.Abp.Identity.MongoDB/Volo/Abp/Identity/MongoDB/MongoIdentityUserRepository.cs
@@ -485,6 +485,14 @@ public class MongoIdentityUserRepository : MongoDbRepository<IAbpIdentityMongoDb
             .ToListAsync(cancellationToken: cancellationToken);
     }
 
+    public virtual async Task<List<IdentityUser>> GetUsersByLoginAsync(string loginProvider, string providerKey, bool includeDetails = false, CancellationToken cancellationToken = default)
+    {
+        return await (await GetQueryableAsync(cancellationToken))
+            .OrderBy(x => x.Id)
+            .Where(u => u.Logins.Any(login => login.LoginProvider == loginProvider && login.ProviderKey == providerKey))
+            .ToListAsync(cancellationToken: cancellationToken);
+    }
+
     public virtual async Task<IdentityUser> FindByNormalizedUserNameAsync(Guid? tenantId, string normalizedUserName, bool includeDetails = true, CancellationToken cancellationToken = default)
     {
         return await (await GetQueryableAsync(cancellationToken))