My pihole docker containers auto-upgraded to 2023.3.0 overnight and I noticed this morning that orbital syncs were failing to apply to other instances. It seems like the backup was fine, but the replication to other pihole instances was failing.
I reverted pihole to 2023.2.0 and it started working again.
3/23/2023, 11:16:32 AM: ➡️ Signing in to http://192.168.1.112:90/admin...
3/23/2023, 11:16:32 AM: ➡️ Signing in to http://192.168.1.86:90/admin...
3/23/2023, 11:16:32 AM: ✔️ Successfully signed in to http://192.168.1.112:90/admin!
3/23/2023, 11:16:32 AM: ➡️ Uploading backup to http://192.168.1.112:90/admin...
3/23/2023, 11:16:32 AM: ✔️ Successfully signed in to http://192.168.1.86:90/admin!
3/23/2023, 11:16:32 AM: ➡️ Uploading backup to http://192.168.1.86:90/admin...
3/23/2023, 11:16:37 AM: ⚠ Error: Failed to upload backup to "http://192.168.1.112:90/admin".
3/23/2023, 11:16:40 AM: ⚠ Error: Failed to upload backup to "http://192.168.1.86:90/admin".
3/23/2023, 11:16:40 AM: ⚠ Failure: 0/2 hosts synced.
3/23/2023, 11:16:42 AM: Waiting 15 minutes...
3/23/2023, 11:31:42 AM: ➡️ Signing in to http://192.168.1.166/admin...
3/23/2023, 11:31:42 AM: ✔️ Successfully signed in to http://192.168.1.166/admin!
3/23/2023, 11:31:42 AM: ➡️ Downloading backup from http://192.168.1.166/admin...
3/23/2023, 11:31:42 AM: ✔️ Backup from http://192.168.1.166/admin completed!
3/23/2023, 11:31:42 AM: ➡️ Signing in to http://192.168.1.112:90/admin...
3/23/2023, 11:31:42 AM: ➡️ Signing in to http://192.168.1.86:90/admin...
3/23/2023, 11:31:42 AM: ✔️ Successfully signed in to http://192.168.1.112:90/admin!
3/23/2023, 11:31:42 AM: ➡️ Uploading backup to http://192.168.1.112:90/admin...
3/23/2023, 11:31:42 AM: ✔️ Successfully signed in to http://192.168.1.86:90/admin!
3/23/2023, 11:31:42 AM: ➡️ Uploading backup to http://192.168.1.86:90/admin...
3/23/2023, 11:31:47 AM: ⚠ Error: Failed to upload backup to "http://192.168.1.112:90/admin".
3/23/2023, 11:31:49 AM: ⚠ Error: Failed to upload backup to "http://192.168.1.86:90/admin".
3/23/2023, 11:31:49 AM: ⚠ Failure: 0/2 hosts synced.
3/23/2023, 11:31:50 AM: Waiting 15 minutes...
3/23/2023, 11:46:50 AM: ➡️ Signing in to http://192.168.1.166/admin...
3/23/2023, 11:46:50 AM: ✔️ Successfully signed in to http://192.168.1.166/admin!
3/23/2023, 11:46:50 AM: ➡️ Downloading backup from http://192.168.1.166/admin...
3/23/2023, 11:46:50 AM: ✔️ Backup from http://192.168.1.166/admin completed!
3/23/2023, 11:46:50 AM: ➡️ Signing in to http://192.168.1.112:90/admin...
3/23/2023, 11:46:50 AM: ➡️ Signing in to http://192.168.1.86:90/admin...
3/23/2023, 11:46:50 AM: ✔️ Successfully signed in to http://192.168.1.86:90/admin!
3/23/2023, 11:46:50 AM: ➡️ Uploading backup to http://192.168.1.86:90/admin...
3/23/2023, 11:46:50 AM: ✔️ Successfully signed in to http://192.168.1.112:90/admin!
3/23/2023, 11:46:50 AM: ➡️ Uploading backup to http://192.168.1.112:90/admin...
3/23/2023, 11:46:56 AM: ⚠ Error: Failed to upload backup to "http://192.168.1.112:90/admin".
3/23/2023, 11:46:57 AM: ⚠ Error: Failed to upload backup to "http://192.168.1.86:90/admin".
3/23/2023, 11:46:57 AM: ⚠ Failure: 0/2 hosts synced.
3/23/2023, 11:46:58 AM: Waiting 15 minutes...
3/23/2023, 12:01:58 PM: ➡️ Signing in to http://192.168.1.166/admin...
3/23/2023, 12:01:58 PM: ✔️ Successfully signed in to http://192.168.1.166/admin!
3/23/2023, 12:01:58 PM: ➡️ Downloading backup from http://192.168.1.166/admin...
3/23/2023, 12:01:58 PM: ✔️ Backup from http://192.168.1.166/admin completed!
3/23/2023, 12:01:58 PM: ➡️ Signing in to http://192.168.1.112:90/admin...
3/23/2023, 12:01:58 PM: ➡️ Signing in to http://192.168.1.86:90/admin...
3/23/2023, 12:01:58 PM: ✔️ Successfully signed in to http://192.168.1.86:90/admin!
3/23/2023, 12:01:58 PM: ➡️ Uploading backup to http://192.168.1.86:90/admin...
3/23/2023, 12:01:58 PM: ✔️ Successfully signed in to http://192.168.1.112:90/admin!
3/23/2023, 12:01:58 PM: ➡️ Uploading backup to http://192.168.1.112:90/admin...
3/23/2023, 12:02:04 PM: ⚠ Error: Failed to upload backup to "http://192.168.1.112:90/admin".
3/23/2023, 12:02:05 PM: ⚠ Error: Failed to upload backup to "http://192.168.1.86:90/admin".
3/23/2023, 12:02:05 PM: ⚠ Failure: 0/2 hosts synced.
3/23/2023, 12:02:06 PM: Waiting 15 minutes...
3/23/2023, 12:17:06 PM: ➡️ Signing in to http://192.168.1.166/admin...
3/23/2023, 12:17:06 PM: ✔️ Successfully signed in to http://192.168.1.166/admin!
3/23/2023, 12:17:06 PM: ➡️ Downloading backup from http://192.168.1.166/admin...
3/23/2023, 12:17:06 PM: ✔️ Backup from http://192.168.1.166/admin completed!
3/23/2023, 12:17:06 PM: ➡️ Signing in to http://192.168.1.112:90/admin...
3/23/2023, 12:17:06 PM: ➡️ Signing in to http://192.168.1.86:90/admin...
3/23/2023, 12:17:06 PM: ✔️ Successfully signed in to http://192.168.1.112:90/admin!
3/23/2023, 12:17:06 PM: ➡️ Uploading backup to http://192.168.1.112:90/admin...
3/23/2023, 12:17:06 PM: ✔️ Successfully signed in to http://192.168.1.86:90/admin!
3/23/2023, 12:17:06 PM: ➡️ Uploading backup to http://192.168.1.86:90/admin...
3/23/2023, 12:17:12 PM: ⚠ Error: Failed to upload backup to "http://192.168.1.112:90/admin".
3/23/2023, 12:17:13 PM: ⚠ Error: Failed to upload backup to "http://192.168.1.86:90/admin".
3/23/2023, 12:17:13 PM: ⚠ Failure: 0/2 hosts synced.
3/23/2023, 12:17:14 PM: Waiting 15 minutes...
3/23/2023, 12:32:15 PM: ➡️ Signing in to http://192.168.1.166/admin...
3/23/2023, 12:32:15 PM: ✔️ Successfully signed in to http://192.168.1.166/admin!
3/23/2023, 12:32:15 PM: ➡️ Downloading backup from http://192.168.1.166/admin...
3/23/2023, 12:32:15 PM: ✔️ Backup from http://192.168.1.166/admin completed!
3/23/2023, 12:32:15 PM: ➡️ Signing in to http://192.168.1.112:90/admin...
3/23/2023, 12:32:15 PM: ➡️ Signing in to http://192.168.1.86:90/admin...
3/23/2023, 12:32:15 PM: ✔️ Successfully signed in to http://192.168.1.86:90/admin!
3/23/2023, 12:32:15 PM: ➡️ Uploading backup to http://192.168.1.86:90/admin...
3/23/2023, 12:32:15 PM: ✔️ Successfully signed in to http://192.168.1.112:90/admin!
3/23/2023, 12:32:15 PM: ➡️ Uploading backup to http://192.168.1.112:90/admin...
3/23/2023, 12:32:20 PM: ✔️ Backup uploaded to http://192.168.1.112:90/admin!
3/23/2023, 12:32:20 PM: ➡️ Updating gravity on http://192.168.1.112:90/admin...
3/23/2023, 12:32:23 PM: ⚠ Error: Failed to upload backup to "http://192.168.1.86:90/admin".
3/23/2023, 12:32:27 PM: ✔️ Gravity updated on http://192.168.1.112:90/admin!
3/23/2023, 12:32:27 PM: ⚠ Failure: 1/2 hosts synced.
3/23/2023, 12:32:29 PM: Waiting 15 minutes...
3/23/2023, 12:47:29 PM: ➡️ Signing in to http://192.168.1.166/admin...
3/23/2023, 12:47:29 PM: ✔️ Successfully signed in to http://192.168.1.166/admin!
3/23/2023, 12:47:29 PM: ➡️ Downloading backup from http://192.168.1.166/admin...
3/23/2023, 12:47:30 PM: ✔️ Backup from http://192.168.1.166/admin completed!
3/23/2023, 12:47:30 PM: ➡️ Signing in to http://192.168.1.112:90/admin...
3/23/2023, 12:47:30 PM: ➡️ Signing in to http://192.168.1.86:90/admin...
3/23/2023, 12:47:30 PM: ✔️ Successfully signed in to http://192.168.1.112:90/admin!
3/23/2023, 12:47:30 PM: ➡️ Uploading backup to http://192.168.1.112:90/admin...
3/23/2023, 12:47:30 PM: ✔️ Successfully signed in to http://192.168.1.86:90/admin!
3/23/2023, 12:47:30 PM: ➡️ Uploading backup to http://192.168.1.86:90/admin...
3/23/2023, 12:47:35 PM: ✔️ Backup uploaded to http://192.168.1.112:90/admin!
3/23/2023, 12:47:35 PM: ➡️ Updating gravity on http://192.168.1.112:90/admin...
3/23/2023, 12:47:37 PM: ✔️ Backup uploaded to http://192.168.1.86:90/admin!
3/23/2023, 12:47:37 PM: ➡️ Updating gravity on http://192.168.1.86:90/admin...
3/23/2023, 12:47:42 PM: ✔️ Gravity updated on http://192.168.1.112:90/admin!
3/23/2023, 12:47:44 PM: ✔️ Gravity updated on http://192.168.1.86:90/admin!
3/23/2023, 12:47:44 PM: ✔️ Success: 2/2 hosts synced.
3/23/2023, 12:47:44 PM: Waiting 15 minutes...