Redshift adjusts the color temperature of your screen according to your surroundings. This may help your eyes hurt less if you are working in front of the screen at night.
Are you able to see the error output from redshift somehow? All I see is that it failed with 'exit-code' which doesn't help much unfortunately. Are you able to run redshift successfully outside of systemd?
failed (Result: start-limit-hit) when I run command [systemctl --user status redshift.service ];It reports `● redshift.service - Redshift display colour temperature adjustment Loaded: loaded (/usr/lib/systemd/user/redshift.service; enabled; vendor preset: enabled) Active: failed (Result: start-limit-hit) since 三 2020-04-29 16:25:19 CST; 1h 8min ago Docs: http://jonls.dk/redshift/ Main PID: 7427 (code=exited, status=1/FAILURE)
4月 29 16:25:18 kylin systemd[1175]: redshift.service: Failed with result 'exit-code'. 4月 29 16:25:19 kylin systemd[1175]: redshift.service: Service hold-off time over, scheduling restart. 4月 29 16:25:19 kylin systemd[1175]: Stopped Redshift display colour temperature adjustment. 4月 29 16:25:19 kylin systemd[1175]: redshift.service: Start request repeated too quickly. 4月 29 16:25:19 kylin systemd[1175]: Failed to start Redshift display colour temperature adjustment. 4月 29 16:25:19 kylin systemd[1175]: redshift.service: Unit entered failed state. 4月 29 16:25:19 kylin systemd[1175]: redshift.service: Failed with result 'start-limit-hit'. 4月 29 17:06:53 kylin systemd[1175]: Stopped Redshift display colour temperature adjustment. 4月 29 17:07:08 kylin systemd[1175]: Stopped Redshift display colour temperature adjustment. 4月 29 17:08:27 kylin systemd[1175]: Stopped Redshift display colour temperature adjustment. Warning: redshift.service changed on disk. Run 'systemctl --user daemon-reload' to reload units.`
uname -a
Linux kylin 5.0.0-32-generic #34kord1 SMP Fri Nov 1 16:54:39 CST 2019 x86_64 x86_64 x86_64 GNU/Linux