InvalidOperationException: No service for type 'Microsoft.AspNetCore.Identity.UserManager`1[Microsoft.AspNetCore.Identity.IdentityUser]' has been registered.
services.AddIdentity<ApplicationUser, IdentityRole>()
.AddEntityFrameworkStores<ApplicationDbContext>()
.AddDefaultTokenProviders()
.AddDefaultUI();
services.AddIdentityCore<StudentUser>()
.AddRoles<IdentityRole>()
.AddClaimsPrincipalFactory<UserClaimsPrincipalFactory<StudentUser, IdentityRole>>()
.AddEntityFrameworkStores<ApplicationDbContext>()
.AddDefaultTokenProviders()
.AddDefaultUI();
services.AddIdentityCore<EmployeeUser>()
.AddRoles<IdentityRole>()
.AddClaimsPrincipalFactory<UserClaimsPrincipalFactory<EmployeeUser, IdentityRole>>()
.AddEntityFrameworkStores<ApplicationDbContext>()
.AddDefaultTokenProviders()
.AddDefaultUI();