Erreur :

• Syntax error or access violation: 1253 COLLATION 'utf8mb4_general_ci' is not valid for CHARACTER SET 'utf8'

Faire :

• https://docs.nextcloud.com/server/17/admin_manual/configuration_database/mysql_4byte_support.html
• https://help.nextcloud.com/t/solved-syntax-error-or-access-violation-1071-specified-key-was-too-long-max-key-length-is-767-bytes/34740

Ne pas oublier d'enlever le mode maintenance

sudo -u www-data php occ maintenance:mode --off

Un exemple pour détecter une erreur lors de la méthode load de jQuery

$( "#success" ).load( "/not-here.php", function( response, status, xhr ) {
  if ( status == "error" ) {
    var msg = "Sorry but there was an error: ";
    $( "#error" ).html( msg + xhr.status + " " + xhr.statusText );
  }
});