Comment # 3 on bug 1034471 from Johannes Meixner

When you can print with Adobe Reader and Ocular
and via command line (lpr command)
but certain programs like Thunderbird, Firefox or LibreOffice
don't even create a print job in CUPS
the issue is in those programs and not in CUPS.

In your attachment#721469 [details]
---------------------------------------------------------------------
E [17/Apr/2017:18:33:32 +0200] [Client 17] Returning IPP
 client-error-document-format-not-supported for Print-Job
 (ipp://localhost:631/printers/Samsung_CLP415) from localhost
---------------------------------------------------------------------
indicates that what those programs try to submit as
print job data to CUPS is a data type that is not supported
by your CUPS setup or by your print queue setup.

See
https://en.opensuse.org/SDB:How_to_Report_a_Printing_Issue
for some basic tests that could help to diagnose
the root cause of your printing issue.
In particular therein see
"Get what the application submits to CUPS"
"Test if what the application had submitted to CUPS seems to be correct"
and
"It always helps to simulate printout on a virtual generic PostScript printer"

I guess Thunderbird, Firefox, and LibreOffice
all use the same lower level tool or library
to submit a print job to CUPS and perhaps
there is an issue in that tool or library.

In this case I cannot help further because I neither know
what tool or library Thunderbird, Firefox, and LibreOffice
use to submit a print job to CUPS nor could I help
to debug such a tool or library.