Been getting these error messages for a while now despite a couple of cPanel updates which I thought might fix it. Their no problem, more of an annoyance:
/usr/local/cpanel/logs/error_log:
[2018-11-12 07:03:11 +0000] warn [tailwatchd] [exim-ports] doesn't look like a service name at /usr/local/cpanel/Cpanel/Services/Installed.pm line 221.
Cpanel::Services::Installed::service_is_installed("exim-ports") called at /usr/local/cpanel/Cpanel/Services/Enabled.pm line 240
Cpanel::Services::Enabled::is_enabled("exim-ports") called at /usr/local/cpanel/Cpanel/TailWatch/ChkServd.pm line 618
Cpanel::TailWatch::ChkServd::_load_config(Cpanel::TailWatch::ChkServd=HASH(0x2540ad8)) called at /usr/local/cpanel/Cpanel/TailWatch/ChkServd.pm line 265
Cpanel::TailWatch::ChkServd::_run_checks(Cpanel::TailWatch::ChkServd=HASH(0x2540ad8), Cpanel::TailWatch=HASH(0x1812480), 1542006191) called at /usr/local/cpanel/Cpanel/TailWatch/ChkServd.pm line 208
Cpanel::TailWatch::ChkServd::run(Cpanel::TailWatch::ChkServd=HASH(0x2540ad8), Cpanel::TailWatch=HASH(0x1812480), 1542006191) called at /usr/local/cpanel/Cpanel/TailWatch.pm line 748
Cpanel::TailWatch::tail_logs(Cpanel::TailWatch=HASH(0x1812480)) called at /usr/local/cpanel/Cpanel/TailWatch.pm line 648
eval {...} called at /usr/local/cpanel/Cpanel/TailWatch.pm line 616
Cpanel::TailWatch::run(Cpanel::TailWatch=HASH(0x1812480)) called at libexec/tailwatch/tailwatchd.pl line 58
main::run("--start") called at libexec/tailwatch/tailwatchd.pl line 35