title: Master user lost it's permissions unexpectedly on SQL Server (rds instance)
body: <p>SQL Server master user lost his permissions unexpectedly. When I try to access my database tables, I get the following error on SSMS: </p>
  
  <blockquote>
    <p>The SELECT permission was denied on the object 'query_store_runtime_stats', database 'mssqlsystemresource', schema 'sys'. (Microsoft SQL Server, Error: 229)</p>
  </blockquote>
  
  <p>If I try to give permission to master user, I get the following error when mapping credentials (Security > Logins > Masteruser > Properties):</p>
  
  <blockquote>
    <p>One or more databases are inaccessible and will not be displayed in list</p>
  </blockquote>
  
  <p>The missing database is the one where my tables/procedures are stored. The end-users are unable to access the database too. </p>
  
  <p>I have tried to grant permission using sql query but even that priviledge is disabled.</p>
  
  <p>The only one user that is able to use that database is a <em>read only</em> user that i have created previously.</p>
  
  <p>I changed my master password on Amazon AWS console, but that didn't solve my problem.</p>
  
  <p>What should I do to solve this issue?</p>