Can not decrypt files via occ - Operation simply aborted

I’am trying to decrypt my files. But if I do so, I get the following output:

    [0] => The process control (PCNTL) extensions are required in case you want to interrupt long running commands - see http://php.net/manual/en/book.pcntl.php
   _    [1] => Maintenance mode enabled
   _    [2] => The process control (PCNTL) extensions are required in case you want to interrupt long running commands - see http://php.net/manual/en/book.pcntl.php
   _    [3] => Nextcloud is in maintenance mode - no apps have been loaded
   _    [4] => 
   _    [5] => Disable server side encryption... done.
   _    [6] => 
   _    [7] => 
   _    [8] => You are about to start to decrypt all files stored in Daniel's account.
   _    [9] => It will depend on the encryption module and your setup if this is possible.
   _    [10] => Depending on the number and size of your files this can take some time
   _    [11] => Please make sure that no user access his files during this process!
   _    [12] => 
   _    [13] => Enable server side encryption... done.
   _    [14] => **aborted**
   _    [15] => The process control (PCNTL) extensions are required in case you want to interrupt long running commands - see http://php.net/manual/en/book.pcntl.php
   _    [16] => Nextcloud is in maintenance mode - no apps have been loaded
   _    [17] => 
   _    [18] => Maintenance mode disabled

The Operation is simply aborted - with no concret error message. Maybe you can help me out?

PCNTL should not be required, not sure if this can perhaps cause some unintentional errors, I would try to install it. Can you provide more infos from your logs? Did you abort the process, did it stop itself? Did it run into a timeout? Did you get the error directly or did it take some time?