thanks again for the fast response - sorry for keeping you waiting so long with an answer.
unfortunately - same result.
I limited the download queue to 4 in paralell - and added debug logging.
when I do a curl from the router on the given urls - they show up correctly.
the problem with youtube is new.
Mon Aug 24 19:05:16 2020 user.debug adblock-4.0.6[19922]: f_dns ::: dns: dnsmasq, dns_dir: /tmp/dnsmasq.d, dns_file: adb_list.overall, dns_user: dnsmasq, dns_inotify: 0, dns_instance: 0, backup: 1, backup_dir: /tmp, jail_dir: /tmp
Mon Aug 24 19:05:16 2020 user.debug adblock-4.0.6[19922]: f_fetch ::: fetch_util: /usr/bin/curl, fetch_parm: --connect-timeout 20 --silent --show-error --location -o
Mon Aug 24 19:05:16 2020 user.debug adblock-4.0.6[19922]: f_bgserv ::: status: stop, bg_pid: -, dns_filereset: 0, ubus_service: /etc/adblock/adblock.monitor
Mon Aug 24 19:05:16 2020 user.debug adblock-4.0.6[19922]: f_report ::: action: reload, report: 1, search: +, count: 50, process: false, print: false, dump_util: /usr/sbin/tcpdump, repdir: /tmp, repiface: br-lan, replisten: 53, repchunksize: 5, repchunkcnt: 5, bg_pid: 18610
Mon Aug 24 19:05:16 2020 user.info adblock-4.0.6[19922]: adblock instance started ::: action: reload, priority: 0, pid: 19922
Mon Aug 24 19:05:17 2020 user.debug adblock-4.0.6[19922]: f_jsnup ::: status: running, cnt: 330243, mail: 0, mail_service: /etc/adblock/adblock.mail, mail_cnt: 0, mail_pid: -
Mon Aug 24 19:05:17 2020 user.debug adblock-4.0.6[19922]: f_uci ::: config: dhcp, change:
Mon Aug 24 19:05:17 2020 user.debug adblock-4.0.6[19922]: f_uci ::: config: firewall, change:
Mon Aug 24 19:05:17 2020 user.debug adblock-4.0.6[19922]: f_temp ::: tmp_base: /tmp, tmp_dir: /tmp/tmp.JiGjAK, cores: 2, sort_options: --temporary-directory=/tmp/tmp.JiGjAK --compress-program=gzip --batch-size=32 --parallel=2, pid_file: /var/run/adblock.pid
Mon Aug 24 19:05:17 2020 user.debug adblock-4.0.6[19922]: f_main ::: memory: 480/265/257, max_queue: 4, safe_search: 0, force_dns: 1, awk: /usr/bin/awk
Mon Aug 24 19:05:17 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: blacklist, mode: blacklist, cnt: 97, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:17 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: whitelist, mode: whitelist, cnt: 18, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:25 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: adaway, mode: download, cnt: 7924, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:25 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: adaway, mode: backup, cnt: 7924, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:34 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: adguard, mode: download, cnt: 35882, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:34 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: adguard, mode: backup, cnt: 35882, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:36 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: anti_ad, mode: download, cnt: 41474, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:36 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: anti_ad, mode: backup, cnt: 41474, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:41 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: andryou, mode: download, cnt: 67422, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:41 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: andryou, mode: backup, cnt: 67422, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:42 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: bitcoin, mode: download, cnt: 687, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:42 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: bitcoin, mode: backup, cnt: 687, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:45 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: disconnect, mode: download, cnt: 2728, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:45 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: disconnect, mode: backup, cnt: 2728, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:53 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: malwaredomains, mode: download, cnt: 26846, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:53 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: malwaredomains, mode: backup, cnt: 26846, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:56 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: anudeep, mode: download, cnt: 42380, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:56 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: anudeep, mode: backup, cnt: 42380, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:58 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: malwarelist, mode: download, cnt: 1104, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:58 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: malwarelist, mode: backup, cnt: 1104, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:58 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: openphish, mode: download, cnt: 1502, in_rc: 0, out_rc: 0
Mon Aug 24 19:05:58 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: openphish, mode: backup, cnt: 1502, in_rc: 0, out_rc: 0
Mon Aug 24 19:06:01 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: phishing_army, mode: download, cnt: 16211, in_rc: 0, out_rc: 0
Mon Aug 24 19:06:01 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: phishing_army, mode: backup, cnt: 16211, in_rc: 0, out_rc: 0
Mon Aug 24 19:06:28 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: notracking, mode: download, cnt: 218195, in_rc: 0, out_rc: 0
Mon Aug 24 19:06:29 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: notracking, mode: backup, cnt: 218195, in_rc: 0, out_rc: 0
Mon Aug 24 19:06:30 2020 user.info adblock-4.0.6[19922]: download of 'reg_de' failed, url: https://easylist-downloads.adblockplus.org/easylistgermany+easylist.txt, rule: BEGIN{FS="[|^]"}/^\|\|([[:alnum:]_-]{1,63}\.)+[[:alpha:]]+\^(\$third-party)?$/{print tolower($3)}, categories: -, rc: 7, log: curl: (7) Error
Mon Aug 24 19:06:30 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: reg_de, mode: restore, cnt: 0, in_rc: 7, out_rc: 4
Mon Aug 24 19:06:30 2020 user.info adblock-4.0.6[19922]: download of 'reg_cn' failed, url: https://easylist-downloads.adblockplus.org/easylistchina+easylist.txt, rule: BEGIN{FS="[|^]"}/^\|\|([[:alnum:]_-]{1,63}\.)+[[:alpha:]]+\^(\$third-party)?$/{print tolower($3)}, categories: -, rc: 7, log: curl: (7) Error
Mon Aug 24 19:06:30 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: reg_cn, mode: restore, cnt: 0, in_rc: 7, out_rc: 4
Mon Aug 24 19:06:31 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: smarttv, mode: download, cnt: 204, in_rc: 0, out_rc: 0
Mon Aug 24 19:06:31 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: smarttv, mode: backup, cnt: 204, in_rc: 0, out_rc: 0
Mon Aug 24 19:06:32 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: spam404, mode: download, cnt: 7064, in_rc: 0, out_rc: 0
Mon Aug 24 19:06:32 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: spam404, mode: backup, cnt: 7064, in_rc: 0, out_rc: 0
Mon Aug 24 19:06:34 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: wally3k, mode: download, cnt: 770, in_rc: 0, out_rc: 0
Mon Aug 24 19:06:34 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: wally3k, mode: backup, cnt: 770, in_rc: 0, out_rc: 0
Mon Aug 24 19:06:37 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: stopforumspam, mode: download, cnt: 10892, in_rc: 0, out_rc: 0
Mon Aug 24 19:06:37 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: stopforumspam, mode: backup, cnt: 10892, in_rc: 0, out_rc: 0
Mon Aug 24 19:06:43 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: winhelp, mode: download, cnt: 9553, in_rc: 0, out_rc: 0
Mon Aug 24 19:06:43 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: winhelp, mode: backup, cnt: 9553, in_rc: 0, out_rc: 0
Mon Aug 24 19:06:45 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: whocares, mode: download, cnt: 14452, in_rc: 0, out_rc: 0
Mon Aug 24 19:06:45 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: whocares, mode: backup, cnt: 14452, in_rc: 0, out_rc: 0
Mon Aug 24 19:07:18 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: utcapitole, mode: download, cnt: 132506, in_rc: 0, out_rc: 0
Mon Aug 24 19:07:18 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: utcapitole, mode: backup, cnt: 132506, in_rc: 0, out_rc: 0
Mon Aug 24 19:07:19 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: winspy, mode: download, cnt: 323, in_rc: 0, out_rc: 0
Mon Aug 24 19:07:19 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: winspy, mode: backup, cnt: 323, in_rc: 0, out_rc: 0
Mon Aug 24 19:07:20 2020 user.info adblock-4.0.6[19922]: preparation of 'youtube' failed, rc: 0
Mon Aug 24 19:07:20 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: youtube, mode: restore, cnt: 0, in_rc: 0, out_rc: 4
Mon Aug 24 19:07:22 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: yoyo, mode: download, cnt: 3524, in_rc: 0, out_rc: 0
Mon Aug 24 19:07:22 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: yoyo, mode: backup, cnt: 3524, in_rc: 0, out_rc: 0
Mon Aug 24 19:07:27 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: -, mode: merge, cnt: 402820, in_rc: 4, out_rc: 0
Mon Aug 24 19:07:43 2020 user.debug adblock-4.0.6[19922]: f_tld ::: source: /tmp/tmp.JiGjAK/adb_list.overall, cnt: 402820, cnt_tld: 330243
Mon Aug 24 19:07:54 2020 user.debug adblock-4.0.6[19922]: f_list ::: name: -, mode: final, cnt: 330243, in_rc: 4, out_rc: 0
Mon Aug 24 19:07:58 2020 user.debug adblock-4.0.6[19922]: f_dnsup ::: lookup_util: /usr/bin/nslookup, lookup_domain: ip.icb.at, restart_rc: 0, dns_timeout: 20, dns_cnt: 2, in_rc: 0, out_rc: 0
Mon Aug 24 19:07:58 2020 user.debug adblock-4.0.6[19922]: f_jsnup ::: status: enabled, cnt: 330243, mail: 0, mail_service: /etc/adblock/adblock.mail, mail_cnt: 0, mail_pid: -
Mon Aug 24 19:07:58 2020 user.info adblock-4.0.6[19922]: blocklist with overall 330243 blocked domains loaded successfully (TP-Link Archer C2600, OpenWrt 19.07.3 r11063-85e04e9f46)
Mon Aug 24 19:07:58 2020 user.debug adblock-4.0.6[19922]: f_rmtemp ::: tmp_dir: /tmp/tmp.JiGjAK, src_file: /tmp/adb_sources.json, pid_file: /var/run/adblock.pid