When the SQL Server bak file is restored, the original user cannot delete the solution.

You cannot create the same user and mapping this user to the database, and you cannot delete the Database User: deoffset.
Run the following script, and then you can delete the user: deoffset. then create the user (deoffset.) and map it to the database.
Script:
Copy codeThe Code is as follows:
GO
Alter authorization on role: [aspnet_Membership_BasicAccess] TO [dbo]
GO
GO
Alter authorization on role: [aspnet_Membership_FullAccess] TO [dbo]
GO
GO
Alter authorization on role: [aspnet_Membership_ReportingAccess] TO [dbo]
GO
GO
Alter authorization on role: [aspnet_Profile_BasicAccess] TO [dbo]
GO
GO
Alter authorization on role: [aspnet_Profile_FullAccess] TO [dbo]
GO
GO
Alter authorization on role: [aspnet_Profile_ReportingAccess] TO [dbo]
GO
GO
Alter authorization on role: [aspnet_Roles_BasicAccess] TO [dbo]
GO
GO
Alter authorization on role: [aspnet_Roles_FullAccess] TO [dbo]
GO
GO
Alter authorization on role: [aspnet_Roles_ReportingAccess] TO [dbo]
GO
GO
Alter authorization on schema: [db_owner] TO [dbo]
GO
GO
Alter authorization on schema: [db_owner] TO [db_owner]
GO