Imap with TYPO3 under Debian

I work on a software which gets it’s data from email attatchments. First I worked outside of the TYPO3 environment and managed to login to the email account via the imap_open() php method. Now the code is integrated in the TYPO3 environment in the form of a Scheduler Task and now i can’t login to the imap server anymore.I now get a “Couldn’t open stream” error message.
More information:

  • I did activate the imap extension for php.
  • the imap server uses a ssl connection with port 993, which I specified in the connection string
  • it looks like this: {mail@domain:993/imap/ssl/validate-cert}INBOX
  • as i said, this configuration already worked outside of the TYPO3 environment
  • I use a Debian Server inside a Virtual Box environment