Analyse following RPM build log snippet. Describe contents accurately, without speculation or suggestions for resolution.            
Your analysis must be as concise as possible, while keeping relevant information intact.
Snippet: 
cmd: ['rpkg', 'srpm', '--outdir', '/var/lib/copr-rpmbuild/results', '--spec', '/var/lib/copr-rpmbuild/workspace/workdir-5nxhm5kx/thunderbird-nightly-copr/thunderbird-nightly.spec']
cwd: /var/lib/copr-rpmbuild/workspace/workdir-5nxhm5kx/thunderbird-nightly-copr
rc: 1
stdout: Wrote: /var/lib/copr-rpmbuild/results/thunderbird-nightly.spec
stderr: warning: Downloading https://ftp.mozilla.org/pub/thunderbird/nightly/latest-comm-central-l10n/thunderbird-92.0a1.en-US.linux-x86_64.tar.bz2 to /var/lib/copr-rpmbuild/results/thunderbird-92.0a1.en-US.linux-x86_64.tar.bz2
curl: (22) The requested URL returned error: 404
error: Executing url helper "/usr/bin/curl --proto -all,+https,+ftps  --silent --show-error --fail --globoff --location -o /var/lib/copr-rpmbuild/results/thunderbird-92.0a1.en-US.linux-x86_64.tar.bz2 https://ftp.mozilla.org/pub/thunderbird/nightly/latest-comm-central-l10n/thunderbird-92.0a1.en-US.linux-x86_64.tar.bz2" failed with status 22
error: Couldn't download https://ftp.mozilla.org/pub/thunderbird/nightly/latest-comm-central-l10n/thunderbird-92.0a1.en-US.linux-x86_64.tar.bz2

Attempt to download remote file `https://ftp.mozilla.org/pub/thunderbird/nightly/latest-comm-central-l10n/thunderbird-92.0a1.en-US.linux-x86_64.tar.bz2` has failed due to error 404.