Upload MDT Bundle - "File upload in progress"

Hello,

I am new in deploying OS via BigFix and I encounter a problem that I can’t manage.
I have deployment share and I want to import it to BigFix. After uploading MDT bundle (during this process I always receive message asking “Stop running this script?” and I click “No”) in “Warnings” column I have a green arrow stating that “File upload in progress”. I waited few hours and this arrow is still there (on our test environment I have never encounter this problem). I am able to create new Bare Metal Profile with this MDT bundle, but when I am trying “Send to Server” option then action always stuck on “Pending Download” and in “Download” section I see something like this:

File----------------------------------------Status--------------Details
someName.wim.BFOSD---------------Complete----------Cached on Server
someName.driverinfo.BFOSD--------Complete----------Cached on Server
hash.zip.BFOSD------------------------Complete----------Cached on Server
otherHash.zip.BFOSD-----------------Failed---------------Download “Unexpected HTTP response: 404 Not Found”

so I assume that first this MDT bundle have be to completely uploaded (this green arrow have to disappear) and only then I will be able to perform next steps?

I found on web information that some logs are stored in "%TEMP%\OSDeployment\UploadManagerFiles"
I have checked and there is a file “uploadmanager_1539238078287_991.log” which ended with those lines:

sent            907017375 /           6433236235 bytes
sent            908065950 /           6433236235 bytes
sent            909114525 /           6433236235 bytes
sent            910163100 /           6433236235 bytes
sent            911211675 /           6433236235 bytes
sent            912260250 /           6433236235 bytes
sent            913308825 /           6433236235 bytes
sent            914357400 /           6433236235 bytes
sent            915405975 /           6433236235 bytes
winhttprecieveresponse failed  timed out, retrying after 1 second.
Retry #1

sent            915405975 /           6433236235 bytes
http response was : File error "class FileIOError" on "D:\Program Files (x86)\BigFix Enterprise\BESServer\wwwrootbes\Temp\_f46eecda5951792312468b57a10b2e40783e873f": Windows Error 0x20: The process cannot access the file because it is being used by another process.
response was not success, retrying after 1 second.

...

Retry #5

sent            915405975 /           6433236235 bytes
http response was : File error "class FileIOError" on "D:\Program Files (x86)\BigFix Enterprise\BES Server\wwwrootbes\Temp\_f46eecda5951792312468b57a10b2e40783e873f": Windows Error 0x20: The process cannot access the file because it is being used by another process.
response was not success, retrying after 1 second.
 TemporaryZipFile_1539237198676_511.zip upload complete.
return code = 2

Could someone help me to figure out what is wrong? What cause those problems?

Best regards,
Mateusz