I do not think that's your actual problem.
Your actual problem is this (although the root cause is the same):
> 2019-09-03 11:19:03.563 Script: get -nopermissions -preservetime -transfer="binary" -- "/inbox/first_file.xml" ".\8bf8c8f1-c2bb-434f-82f1-ed4d49a7a462\"
> 2019-09-03 11:19:03.563 Script: Switch: -nopermissions
> 2019-09-03 11:19:03.563 Script: Switch: -preservetime
> 2019-09-03 11:19:03.563 Script: Switch: -transfer=binary
> 2019-09-03 11:19:03.563 Script: Parameter: /inbox/first_file.xml
> 2019-09-03 11:19:03.563 Script: Parameter: .\8bf8c8f1-c2bb-434f-82f1-ed4d49a7a462\
. 2019-09-03 11:19:03.563 Listing file "/inbox/first_file.xml".
. 2019-09-03 11:19:03.563 Retrieving file information...
> 2019-09-03 11:19:03.563 PWD
< 2019-09-03 11:19:03.626 257 "/inbox/" is the current directory.
> 2019-09-03 11:19:03.626 CWD /inbox/first_file.xml
< 2019-09-03 11:19:03.673 550 No such file or directory
> 2019-09-03 11:19:03.673 TYPE I
< 2019-09-03 11:19:03.735 200 OK
> 2019-09-03 11:19:03.735 SIZE /inbox/first_file.xml
< 2019-09-03 11:19:03.798 213 5728
> 2019-09-03 11:19:03.798 MDTM /inbox/first_file.xml
< 2019-09-03 11:19:03.860 213 1567495272
. 2019-09-03 11:19:03.860 Could not retrieve file information
. 2019-09-03 11:19:03.860 Got reply 4 to the command 1024
< 2019-09-03 11:19:03.860 Script: Can't get attributes of file '/inbox/first_file.xml'.
< 2019-09-03 11:19:03.860 Could not retrieve file information
. 2019-09-03 11:19:03.860 Script: Failed
Your server is buggy. The response to the
MDTM command should be a timestamp in a format
YYYYMMDDHHMMSS:
https://datatracker.ietf.org/doc/html/rfc3659#section-3.1
https://datatracker.ietf.org/doc/html/rfc3659#section-2.3
While what your server seems to return is a Unix epoch timestamp.
