E-Mails not sent

Hello,

my last email notifications were not sent. They all are in the subscriptions queue table, but when running cron.php nothing happens.

The drupal log says that cron exceeded time limit.
The php settings max_execution_time are set to 120
The subscribtions settings are set to use 100% of cron time.

Normaly as much as possible emails were sent and the next with another cron, but now nothing happens .

Actually I don't know, why this does not work anymore, as I did not change much the last days...
Which other settings could be involved? What could I change to get the mails sent?

Regards

Adriana