Same issue at my site. I'm using mailman3 3.3.8 shipped with Debian 12. To debug the problem I stopped apache, cron, postfix and mailman3-web services. But I still get the mariadb aborted connection warnings every 5 minutes. 2024-01-30T19:26:42.272261+01:00 debian12 mariadbd[666]: 2024-01-30 19:26:42 62184 [Warning] Aborted connection 62184 to db: 'mailman3' user: 'mailman3' host: 'localhost' (Got an error reading communication packets) 2024-01-30T19:31:42.434576+01:00 debian12 mariadbd[666]: 2024-01-30 19:31:42 62185 [Warning] Aborted connection 62185 to db: 'mailman3' user: 'mailman3' host: 'localhost' (Got an error reading communication packets) 2024-01-30T19:36:42.653755+01:00 debian12 mariadbd[666]: 2024-01-30 19:36:42 62186 [Warning] Aborted connection 62186 to db: 'mailman3' user: 'mailman3' host: 'localhost' (Got an error reading communication packets) This is what appears in the database debug log for the connection number 62186. 240130 19:36:42 62186 Connect mailman3@localhost on mailman3 using TCP/IP 62186 Query SET AUTOCOMMIT = 0 62186 Query SET SESSION TRANSACTION ISOLATION LEVEL READ UNCOMMITTED 62186 Query COMMIT 62186 Query SET NAMES utf8 62186 Query SELECT VERSION() 62186 Query SELECT DATABASE() 62186 Query SELECT @@tx_isolation 62186 Query SELECT @@sql_mode 62186 Query SELECT @@lower_case_table_names 62186 Query ROLLBACK 62186 Query SELECT COUNT(*) FROM information_schema.tables WHERE table_schema = 'mailman3' AND table_name = 'alembic_version' 62186 Query SELECT alembic_version.version_num 62186 Query COMMIT 62186 Query ROLLBACK 62186 Query SELECT mailinglist.list_id AS mailinglist_list_id, mailinglist.preferred_language AS mailinglist_preferred_language, mailinglist.id AS mailinglist_id, mailinglist.list_name AS mailinglist_list_name, mailinglist.mail_host AS mailinglist_mail_host, mailinglist.allow_list_posts AS mailinglist_allow_list_posts, mailinglist.include_rfc2369_headers AS mailinglist_include_rfc2369_headers, mailinglist.advertised AS mailinglist_advertised, mailinglist.anonymous_list AS mailinglist_anonymous_list, mailinglist.created_at AS mailinglist_created_at, mailinglist.next_request_id AS mailinglist_next_request_id, mailinglist.next_digest_number AS mailinglist_next_digest_number, mailinglist.digest_last_sent_at AS mailinglist_digest_last_sent_at, mailinglist.volume AS mailinglist_volume, mailinglist.last_post_at AS mailinglist_last_post_at, mailinglist.accept_these_nonmembers AS mailinglist_accept_these_nonmembers, mailinglist.admin_immed_notify AS mailinglist_admin_immed_notify, mailinglist.admin_notify_mchanges AS mailinglist_admin_notify_mchanges, mailinglist.administrivia AS mailinglist_administrivia, mailinglist.archive_policy AS mailinglist_archive_policy, mailinglist.autoresponse_grace_period AS mailinglist_autoresponse_grace_period, mailinglist.autorespond_owner AS mailinglist_autorespond_owner, mailinglist.autoresponse_owner_text AS mailinglist_autoresponse_owner_text, mailinglist.autorespond_postings AS mailinglist_autorespond_postings, mailinglist.autoresponse_postings_text AS mailinglist_autoresponse_postings_text, mailinglist.autorespond_requests AS mailinglist_autorespond_requests, mailinglist.autoresponse_request_text AS mailinglist_autoresponse_request_text, mailinglist.filter_action AS mailinglist_filter_action, mailinglist.filter_content AS mailinglist_filter_content, mailinglist.collapse_alternatives AS mailinglist_collapse_alternatives, mailinglist.convert_html_to_plaintext AS mailinglist_convert_html_to_plaintext, mailinglist.bounce_info_stale_after AS mailinglist_bounce_info_stale_after, mailinglist.bounce_matching_headers AS mailinglist_bounce_matching_headers, mailinglist.bounce_notify_owner_on_bounce_increment AS mailinglist_bounce_notify_owner_on_bounce_increment, mailinglist.bounce_notify_owner_on_disable AS mailinglist_bounce_notify_owner_on_disable, mailinglist.bounce_notify_owner_on_removal AS mailinglist_bounce_notify_owner_on_removal, mailinglist.bounce_score_threshold AS mailinglist_bounce_score_threshold, mailinglist.bounce_you_are_disabled_warnings AS mailinglist_bounce_you_are_disabled_warnings, mailinglist.bounce_you_are_disabled_warnings_interval AS mailinglist_bounce_you_are_disabled_warnings_interval, mailinglist.forward_unrecognized_bounces_to AS mailinglist_forward_unrecognized_bounces_to, mailinglist.process_bounces AS mailinglist_process_bounces, mailinglist.dmarc_mitigate_action AS mailinglist_dmarc_mitigate_action, mailinglist.dmarc_mitigate_unconditionally AS mailinglist_dmarc_mitigate_unconditionally, mailinglist.dmarc_moderation_notice AS mailinglist_dmarc_moderation_notice, mailinglist.dmarc_wrapped_message_text AS mailinglist_dmarc_wrapped_message_text, mailinglist.default_member_action AS mailinglist_default_member_action, mailinglist.default_nonmember_action AS mailinglist_default_nonmember_action, mailinglist.description AS mailinglist_description, mailinglist.digests_enabled AS mailinglist_digests_enabled, mailinglist.digest_is_default AS mailinglist_digest_is_default, mailinglist.digest_send_periodic AS mailinglist_digest_send_periodic, mailinglist.digest_size_threshold AS mailinglist_digest_size_threshold, mailinglist.digest_volume_frequency AS mailinglist_digest_volume_frequency, mailinglist.discard_these_nonmembers AS mailinglist_discard_these_nonmembers, mailinglist.emergency AS mailinglist_emergency, mailinglist.encode_ascii_prefixes AS mailinglist_encode_ascii_prefixes, mailinglist.first_strip_reply_to AS mailinglist_first_strip_reply_to, mailinglist.forward_auto_discards AS mailinglist_forward_auto_discards, mailinglist.gateway_to_mail AS mailinglist_gateway_to_mail, mailinglist.gateway_to_news AS mailinglist_gateway_to_news, mailinglist.hold_these_nonmembers AS mailinglist_hold_these_nonmembers, mailinglist.info AS mailinglist_info, mailinglist.linked_newsgroup AS mailinglist_linked_newsgroup, mailinglist.max_days_to_hold AS mailinglist_max_days_to_hold, mailinglist.max_message_size AS mailinglist_max_message_size, mailinglist.max_num_recipients AS mailinglist_max_num_recipients, mailinglist.member_moderation_notice AS mailinglist_member_moderation_notice, mailinglist.moderator_password AS mailinglist_moderator_password, mailinglist.newsgroup_moderation AS mailinglist_newsgroup_moderation, mailinglist.nntp_prefix_subject_too AS mailinglist_nntp_prefix_subject_too, mailinglist.nonmember_rejection_notice AS mailinglist_nonmember_rejection_notice, mailinglist.obscure_addresses AS mailinglist_obscure_addresses, mailinglist.owner_chain AS mailinglist_owner_chain, mailinglist.owner_pipeline AS mailinglist_owner_pipeline, mailinglist.personalize AS mailinglist_personalize, mailinglist.post_id AS mailinglist_post_id, mailinglist.posting_chain AS mailinglist_posting_chain, mailinglist.posting_pipeline AS mailinglist_posting_pipeline, mailinglist.display_name AS mailinglist_display_name, mailinglist.reject_these_nonmembers AS mailinglist_reject_these_nonmembers, mailinglist.reply_goes_to_list AS mailinglist_reply_goes_to_list, mailinglist.reply_to_address AS mailinglist_reply_to_address, mailinglist.require_explicit_destination AS mailinglist_require_explicit_destination, mailinglist.respond_to_post_requests AS mailinglist_respond_to_post_requests, mailinglist.member_roster_visibility AS mailinglist_member_roster_visibility, mailinglist.scrub_nondigest AS mailinglist_scrub_nondigest, mailinglist.send_goodbye_message AS mailinglist_send_goodbye_message, mailinglist.send_welcome_message AS mailinglist_send_welcome_message, mailinglist.subject_prefix AS mailinglist_subject_prefix, mailinglist.subscription_policy AS mailinglist_subscription_policy, mailinglist.topics AS mailinglist_topics, mailinglist.topics_bodylines_limit AS mailinglist_topics_bodylines_limit, mailinglist.topics_enabled AS mailinglist_topics_enabled, mailinglist.unsubscription_policy AS mailinglist_unsubscription_policy, mailinglist.usenet_watermark AS mailinglist_usenet_watermark, mailinglist.archive_rendering_mode AS mailinglist_archive_rendering_mode 62186 Query COMMIT 62186 Query ROLLBACK The regular mailman log doesn't show anything and I'm not sure about how to enable an appropriate debug log for mailman.