Hello,
I am experiencing a reproducible attachment-download issue in Grommunio Web.
Environment
- Grommunio appliance: grommunio-release 2026.06.1
- OS: openSUSE Leap 16.0
- gromox: 3.10.261.m1826fe0-lp160.56.1
- grommunio-web: 5.0.66.gc7c94cea8-lp160.685.3
- nginx and PHP-FPM
- Mailbox: demouge@domain.nl
- Web client is accessed through an nginx reverse proxy, but the exact same result is also logged by the appliance's internal nginx.
Problem
In Grommunio Web, every attachment download results in a zero-byte file called ERROR.
PDF preview also shows “0 of 0 pages” / no preview. This affects PDF files, images, and attachments from both imported and newly received messages.
The message body and attachment metadata/size are visible normally in Grommunio Web. For example, Web reports a PDF as 35.2 KB, but downloading it creates a 0-byte ERROR file.
Observed HTTP behaviour
The Grommunio Web endpoint returns HTTP 200 with a zero-byte response:
GET /web/index.php?...&load=download_attachment... HTTP/2.0
200 0
This is visible in both:
- reverse-proxy nginx access log;
- appliance nginx-web-access.log.
There are no relevant PHP-FPM, grommunio-web, gromox-http, or gromox-zcore log messages when reproducing the download.
Storage verification
The mailbox store itself appears healthy:
find /var/lib/gromox/user/domain.nl/demouge/cid -type f | wc -l
261651
find /var/lib/gromox/user/domain.nl/demouge/eml -type f | wc -l
5
gromox-mbsize /var/lib/gromox/user/domain.nl/demouge
== FS: Body compression analysis ==
Missing items 0 0
== FS: Attachment compression analysis ==
Missing items 0 0
Tracked attachments in cid/ 2554 MB 2586 MB
Direct Gromox export works
For an affected message, Grommunio Web reports this Object ID:
216247/0x34cb7; folder=13/0xd;
dbguid=0a000000a5187b6fbcdcea1ed03c5657;
store=44a779f49e65c14888d37609d4749aa2
Exporting that exact message directly succeeds:
gromox-exm2eml -u demouge@domain.nl 0x34cb7 > /root/testmail-34cb7.eml
echo "exitcode=$?"
exitcode=0
ls -lh /root/testmail-34cb7.eml
-rw-r--r-- 1 root root 294K ... /root/testmail-34cb7.eml
The exported RFC5322 file contains the affected attachment:
Content-Disposition: attachment; filename="Factuur 31147.pdf";
Content-Transfer-Encoding: base64
Content-Type: application/pdf;
Actions already tried
- Verified mailbox directory ownership and permissions:
grommunio:gromox, mode 770.
- Verified sufficient disk space.
- Restarted gromox-zcore and php-fpm.
- Verified packages:
rpm -V grommunio-web gromox
(no output / no modified package files)
- Confirmed no newer grommunio-web package is available in the configured repository.
- Confirmed the client IP is not blocked by CrowdSec.
- Tested a temporary smaller Grommunio Web BLOCK_SIZE setting; no change, then reverted it.
Question
What can cause grommunio-web's download_attachment handler to return an empty HTTP 200 response, while gromox-exm2eml can export the exact same MAPI message including attachments successfully?
I can provide the affected MT/EML export, relevant sanitized configuration, or further diagnostics if needed.
Kind regards,
demouge
