If you got blank screen while connecting to Box, Dropbox, Google Drive, OneDrive one of the reasons for that could be PHP suhosin extension.
Suhosin (pronounced ‘su-ho-shin’) is an advanced protection system for PHP installations. It was designed to protect servers and users from known and unknown flaws in PHP applications and the PHP core. Suhosin comes in two independent parts, that can be used separately or in combination. The first part is a small patch against the PHP core, that implements a few low-level protections against buffer overflows or format string vulnerabilities and the second part is a powerful PHP extension that implements numerous other protections.
You need to change max length of the GET variables. This can be done via PHP suhosin configuration (php.ini or suhosin.ini) called:
suhosin.get.max_value_length = 512 (default value)
suhosin.get.max_value_length = 1024