During a run of 'debdelta-upgrade' today, it gave up with:
...
Delta is not present: gnome-subtitles_1.1-1_1.1-2.1_i386.debdelta
Delta is not present: gnucash_1%3a2.2.9-11_1%3a2.4.7-1_i386.debdelta
debdelta-upgrade : <class 'httplib.BadStatusLine'>
Ran it again. The 'BadStatusLine' error didn't occur after 'gnucash'.
The error appeared later in the run after 'p7zip-full':
% debdelta-upgrade ; echo $?
...
Delta is not present: p7zip_9.04~dfsg.1-1_9.20.1~dfsg.1-3_i386.debdelta
Delta is not present: p7zip-full_9.04~dfsg.1-1_9.20.1~dfsg.1-3_i386.debdelta
debdelta-upgrade : <class 'httplib.BadStatusLine'>
4
Tried again with '-vv':
% debdelta-upgrade -vv ; echo $?
...
Looking for a delta for libgtkmathview0c2a from 0.8.0-5 to 0.8.0-7
Delta is not present: libgtkmathview0c2a00.8.0-5 0.8.0-7 i386.debdelta
No deb-policy "u", no download of http://http.us.debian.org/debian/pool/main/g/gtkmathview/$
Looking for a delta for libgtkmm-2.4-1c2a from 1:2.20.3-1 to 1:2.24.0-1
debdelta-upgrade : <class 'httplib.BadStatusLine'>
4
Hope this helps...