gtk-redshift autostart works, but with error prompt

[thesoundhead]

I finally got gtk-redshift running on Ubuntu 16.04 gnome. Everytime I start the system, I get this error prompt, though:
"Failed to run Redshift fopen: No such file or directory Unable to load config file."
My redshift.conf file looks like this (The latitude and longitude values are dummy values here):

; Global settings for redshift
[redshift]
; Set the day and night screen temperatures
temp-day=5700
temp-night=3500

; Enable/Disable a smooth transition between day and night
; 0 will cause a direct change from day to night screen temperature.
; 1 will gradually increase or decrease the screen temperature.
transition=1

; Set the screen brightness. Default is 1.0.
;brightness=0.9
; It is also possible to use different settings for day and night
; since version 1.8.
;brightness-day=0.7
;brightness-night=0.4
; Set the screen gamma (for all colors, or each color channel
; individually)
gamma=0.8
;gamma=0.8:0.7:0.8
; This can also be set individually for day and night since
; version 1.10.
;gamma-day=0.8:0.7:0.8
;gamma-night=0.6

; Set the location-provider: 'geoclue', 'geoclue2', 'manual'
; type 'redshift -l list' to see possible values.
; The location provider settings are in a different section.
; location-provider=manual
location-provider=geoclue2

; Set the adjustment-method: 'randr', 'vidmode'
; type 'redshift -m list' to see all possible values.
; 'randr' is the preferred method, 'vidmode' is an older API.
; but works in some cases when 'randr' does not.
; The adjustment method settings are in a different section.
adjustment-method=randr

; Configuration of the location-provider:
; type 'redshift -l PROVIDER:help' to see the settings.
; ex: 'redshift -l manual:help'
; Keep in mind that longitudes west of Greenwich (e.g. the Americas)
; are negative numbers.
[manual]
lat=36.0
lon=10.0

; Configuration of the adjustment-method
; type 'redshift -m METHOD:help' to see the settings.
; ex: 'redshift -m randr:help'
; In this example, randr is configured to adjust screen 1.
; Note that the numbering starts from 0, so this is actually the
; second screen. If this option is not specified, Redshift will try
; to adjust _all_ screens.
[randr]
screen=0

Any ideas, how I can fix this?

Edit:
The error only occurs, when I use the -c option with the path to my redshift.conf file... There is no error, when I run the program without any options on startup!

[jonls]

What exactly is the command line you are trying to run?

[knrdkos]

I encountered the same problem with command as:
redshift-gtk -c ~/.config/redshift.conf

fixed it with changing relative path to absolute path for .conf file