#28000Access denied for user @localhost (using password: NO)

#28000Access denied for user @localhost (using password: NO)

I have a large application where i :
  1. i have 14 datamodules.
  2. there's 1 main datamodule which contains the MyConnection component which is set at runtime and at design-time the connectionstring is empty 
  3. every datamodule has a OnCreate event
  4. on all datamodules all query components Active=False

When i open my project i always get this 'error' :
#28000Access denier for user @localhost (using password: NO)

This is the same when the connection string is empty and set MyConnection.Connected := True;

But..no code will be executed when opening a project...what causes this error ?

I use MySQL DAta acces Components  Prof. v. 12.4.0 with Rad Studio 12 Version 29.0.51961.7529