Hi All, We have a mail server running on latest OS X. It does not accept plain text authentication. I have been trying to configure POP3S on OTRS 4 & 5 without success. The OS X Server keep receiving PLAIN method request from OTRS. Perl module Net::POP3S and DIGEST::MD5 are installed. The server is running CentOS7. Below is the error message returned by OTRS. Backend ERROR: OTRS-CGI-10 Perl: 5.16.3 OS: linux Time: Tue Oct 27 12:49:09 2015 Message: POP3S: Auth for user xxxxuser/xxxxxxhost failed! RemoteAddress: x.x.x.x RequestURI: /otrs/index.pl?Action=AdminMailAccount;Subaction=Run;ID=1;ChallengeToken=xxxrandomtokenxxxx; Traceback (2170): Module: Kernel::System::MailAccount::POP3::Fetch Line: 144 Module: Kernel::System::MailAccount::MailAccountFetch Line: 440 Module: Kernel::Modules::AdminMailAccount::Run Line: 54 Module: Kernel::System::Web::InterfaceAgent::Run Line: 1036 Module: ModPerl::ROOT::ModPerl::Registry::opt_otrs_bin_cgi_2dbin_index_2epl::handler Line: 40 Module: (eval) (v1.99) Line: 207 Module: ModPerl::RegistryCooker::run (v1.99) Line: 207 Module: ModPerl::RegistryCooker::default_handler (v1.99) Line: 173 Module: ModPerl::Registry::handler (v1.99) Line: 32 Is there any extra configuration that i need to do other than choosing POP3S in the dropdown list when adding POP account? Best Regards Soragan