We could see inconsistent download speeds from the server. Sometimes when we download the http://database.clamav.net/main-55.cdiff file it completes, other times it just hangs for minutes until it times out:

ERROR: getpatch: Can't download main-55.cdiff from database.clamav.net

ERROR: Can't download main.cvd from database.clamav.net

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# curl  http://database.clamav.net/main-55.cdiff  > test
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
 30 33.1M   30 10.1M    0     0  72463      0  0:07:59  0:02:27  0:05:32     0

#  /usr/local/cpanel/3rdparty/bin/freshclam
ClamAV update process started at Sat Aug 17 08:05:03 2019
WARNING: Your ClamAV installation is OUTDATED!
WARNING: Local version: 0.101.2 Recommended version: 0.101.3
DON'T PANIC! Read https://www.clamav.net/documents/upgrading-clamav
Downloading main-55.cdiff [  1%]
nonblock_recv: recv timing out (120 secs)
WARNING: getfile: Download interrupted: Operation now in progress (IP: 104.16.219.84)
WARNING: getpatch: Can't download main-55.cdiff from database.clamav.net
Downloading main-55.cdiff [ 67%]
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