Error: ArgumentNullException After a Move or an Upgrade

DNN Version: 09.02.00

12/08/2019 • 3 minutes to read

Contributors 

12/08/2019  • 3 minutes to read  • Contributors 

Symptom

Error:

System.ArgumentNullException: Collection cannot be null.

Possible Cause

The database user does not have owner rights for the database.

Solution

1. In the Microsoft SQL Server Management Studio, log into your database server.
2. Go to Security > Logins.
3. Right-click the database associated with your DNN installation, and choose Properties.
4. In the User Mapping section, set the role for the DNN database user as db_owner.

Possible Cause

The IIS bindings do not match the correct portal alias.

Solution

• Correct the site alias in the IIS Manager.

  1. Go to IIS Manager and select the site.
  2. On the right panel, in the Actions section, go to Bindings.
  3. Add a new binding.
  4. Copy the correct site alias into the new binding.

• Correct the site alias in the SQL database.

  1. In the Microsoft SQL Server Management Studio, log in to your database server.

  2. Create a new query for the DNN database.

  3. Run the following: SELECT * FROM PortalAlias

  4. If the result shows an incorrect site alias, replace it.

     Run the following SQL script:

     
     UPDATE PortalAlias
     SET HTTPAlias = 'newdomain.dnndev.me'
     WHERE HTTPAlias = 'olddomain.dnndev.me'
     
     

  5. If the result does not show the site alias, insert it.

     Run the following SQL script:

     
     INSERT INTO PortalAlias (PortalID, HTTPAlias, CreatedByUserID, CreatedOnDate, LastModifiedByUserID, LastModifiedOnDate, BrowserType, IsPrimary)
     VALUES (0,'newdomain.dnndev.me',-1,GETDATE(),-1,GETDATE(),'Normal',0)
     
     

  Note

  When using external domains, you might need to add an entry to %SystemRoot%\System32\drivers\etc\hosts in order to point the browser to the correct domain.

Possible Cause

Incorrect connectionString entry in the web.config file.

Solution

1. Go to the web.config file on the root folder of the installation.
2. Revise the entries for the connection string, specifically Server Name, User, and Password.

Possible Cause

The Application Pool Identity account does not have modify rights for the DNN Installation folder.

Solution

1. Using Windows Explorer, go to your site folder and right-click on the DNN installation folder.
2. Choose Properties, and go to the Security tab.
3. Click/Tap Edit….
4. Click/Tap Add….
5. Select the correct location for the user.
6. Set the object name to IIS AppPool\, where is the Application Pool Identity account name.
7. Click/Tap Check Names.
8. Click/Tap OK, then Apply.

How to: Increase the Maximum File Size for UploadError: Login IP Filtering Is Currently DisabledError: Another User Has Taken Action on the PageError: Unknown Server Tag - DNNComboBoxError: Could not load file or assembly 'AWSSDK' or one of its dependenciesError: SQL TimeoutTroubleshooting: Missing Resources After An UpgradeTroubleshooting: Mixed-Content Warnings When Using SSL OffloadingTroubleshooting: Profile Image Not ShownTroubleshooting: Page Remains in Draft ModeTroubleshooting: Unable to Remove Page Redirect URLsTroubleshooting: Site Theme Does Not LoadTroubleshooting: Incomplete Content LocalizationTroubleshooting: Missing Persona Bar