Debugging dynamic text overlay on SVG images

[gcor71]

After the rather smart @Suvrutt_Gurjar , I have attempted to make my own terribly simple SVG image with text overlay, but can't seem to get it right - ending up with a small warning triangle every time.

Expert eyes that can spot (and guide me) on my rookie mistakes would be appreciated.
My effort is based - possibly too closely - on https://www.googlecloudcommunity.com/gc/Tips-Tricks/Dashboards-with-dynamic-text-overlay-on-SVG-imag...

I have the following columns defined:

• _backdrop : Long text : Virtual column

"data:image/svg+xml;base64,PHN2ZyB3aWR0aD0iNTAwIiBoZWlnaHQ9IjUwMCIgdmlld0JveD0iMCAwIDUwMCA1MDAiIGZpbGw9Im5vbmUiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyI+CjxyZWN0IGlkPSJSZWN0YW5nbGUgMSIgd2lkdGg9IjUwMCIgaGVpZ2h0PSI1MDAiIGZpbGw9IiM4RDREQ0MiLz4KPC9zdmc+Cg=="​

• _attribute : Text : Virtual column

"MEMBER NAME"​

• SVG : Image : Virtual column

CONCATENATE("data&colon;image/svg+xml;utf8,<svg version=""1.1""
     xmlns=""http://www.w3.org/2000/svg"" xmlns:xlink=""http://www.w3.org/1999/xlink""
     width=""500"" height=""500"">
  
     <image x=""0"" y="" 0 "" width=""500"" height=""500""
      xlink:href=""",[_backdrop],"""/>
     
    <text font-family=""Verdana"" font-size=""25""  x=""170"" y=""140"" 
               fill=""rgb(46, 139, 87)"">",[_attribute],"</text>
 </svg>")​

• The result:
  

Thank you, in advance.