I've seen many get this same error so i readed on SQL. I tried this solution and it worked, i hope it helps.

    <add
      name="SiteSqlServer"
      connectionString="Server=(local);Database=DotNetNuke;uid=;Trusted_Connection=yes;pwd=;"
      providerName="System.Data.SqlClient" />

You just have to add between the id and pwd this: Trusted_Connection=yes

Best regards, Fernando.

In certain cases trusted connections will work as long as the Windows User accounts have access to the database.  Typically in hosted environments you cannot use trusted connections.

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-Mitchel Sellers
Microsoft MVP, ASPInsider, DNN MVP
CEO/Director of Development - IowaComputerGurus Inc.


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Keep your trusted_connection=yes in your sql connection string, and use an identity impersionation key in your web.config key.

example:
...
<system.web>
<identity impersonate="true" userName="yourname" password="yoursupersecretpassword"/>
...