Article ID: 126232, created on Jul 17, 2015, last review on Jul 20, 2015

  • Applies to:
  • Plesk 12.0 for Linux


Unable to open one or few messages in Horde webmail, this error is shown instead of message in new window:

Class 'Math_BigInteger' not found [pid 7517 on line 172 of "/usr/share/psa-pear/pear/php/Horde/Mapi.php"]

Also this error message is shown:

Error when communicating with the server


This is a software issue with internal id PPPM-3090 and it will be fixed in further Plesk updates.


As workaround, install and copy this module to required directory:

# /usr/share/psa-pear/pear/pear install Math_BigInteger
# cp -R /usr/share/pear/Math/ /usr/share/psa-pear/pear/php/

Search Words

unable to open message in horde

Class 'Math_BigInteger' not found


Error when communicating with the server

Class Math_BigInteger not found


class not found horde

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