Fatal error: Call to undefined function mb_ substr( ) Error. server, you may simply use EasyApache to recompile PHP with mbstring support. Status: Not a bug, Package: OpenSSL related. I am trying to use the ftp_ ssl_ connect( ) function, however I get Fatal error: Call to undefined function: ftp_ ssl_ connect( ). The only information I have found regarding this issue is located at php. net/ manual/ en/ function. ftp- ssl- connect. php and net/ manual/ en/ ref. ftp_ connect( ) opens an FTP connection to the. - Closes an FTP connection; ftp_ ssl_ connect( ). path1/ path2/, and return an FTP connection resource.