Hello Everyone, We have OTRS 3.3.5 running over CentOS release 6.5 server, the system was running smoothly for a long time, but suddenly we are not able to send emails. We are getting the below error: Error Message: Impossible to send message to: msergani@gmail.com . Backend ERROR: OTRS-CGI-10 Perl: 5.10.1 OS: linux Time: Thu Mar 31 14:41:11 2016 Message: Impossible to send message to: akamel@sygmatel.com . RemoteAddress: x.x.x.x RequestURI: /otrs/index.pl Traceback (2056): Module: Kernel::System::Ticket::Article::ArticleSend (OTRS 3.3.5) Line: 2083 Module: Kernel::Modules::AgentTicketEmail::Run (OTRS 3.3.5) Line: 1291 Module: Kernel::System::Web::InterfaceAgent::Run (OTRS 3.3.5) Line: 871 Module: ModPerl::ROOT::ModPerl::Registry::opt_otrs_bin_cgi_2dbin_index_2epl::handler (unknown version) Line: 41 Module: (eval) (v1.99) Line: 204 Module: ModPerl::RegistryCooker::run (v1.99) Line: 204 Module: ModPerl::RegistryCooker::default_handler (v1.99) Line: 170 Module: ModPerl::Registry::handler (v1.99) Line: 31 We are using Google Apps as our mail server with the below setup: SendmailModule == SMTPTLS SendmailModule::Host == smtp.gmail.com SendmailModule::Port == 465 We can ping, traceroute and telnet "smtp.gmail.com without any issues. Please let us know your thoughts. Thanks //M