title: Firebase Analytics. Can not add custom parameter to event
body: <p>I am trying to add a parameter to my event, but receiving an error "Internal error Please try again later".</p>
  
  <p>I have no registered any parameter yet (0 text and 0 number). 
  After pressing save button I receive following error messages</p>
  
  <ul>
  <li><p>Internal error. Please try again later. (in the center)</p></li>
  <li><p>One or more parameters have not been registered. Please try again (in the top right side)</p></li>
  </ul>
  
  <p>Here is the steps...</p>
  
  <ol>
  <li>Add the parameter </li>
  </ol>
  
  <p><a href="https://i.stack.imgur.com/fis3T.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/fis3T.png" alt="enter image description here"></a></p>
  
  <ol start="2">
  <li>Select parameter type "Text"</li>
  </ol>
  
  <p><a href="https://i.stack.imgur.com/6GrOI.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/6GrOI.png" alt="enter image description here"></a></p>
  
  <ol start="3">
  <li>After "Save" button click, I'm receiving fallowing error messages </li>
  </ol>
  
  <p><a href="https://i.stack.imgur.com/cPnlv.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/cPnlv.png" alt="enter image description here"></a></p>