Dear @Adelheid , what happen if you increase the time the application wait for an answer from the DB on config.php ?
For instance you can set
'resource_management' =>
array (
'special_query_limit' => 5000000,
'special_query_modules' =>
array (
0 => 'Reports',
1 => 'Export',
2 => 'Import',
3 => 'Administration',
4 => 'Sync',
5 => 'AOR_Reports',
6 => 'Leads'
),
'default_limit' => 200000,
),
I also quote Matthew Lorimer: