Connection failure maybe

Support
1

Was in the middle of a backup that has been running for about a week and this evening got an error-

Failed: 500 - internal_error: class org.apache.http.conn.HttpHostConnectException - Connect to sfcentral-0002.local:8180 [sfcentral-0002.local/172.16.2.161] failed: Connection refused (Connection refused) (http://sfcentral-0002.local:8180/b2_internal/authorize_account)
Details: System.Exception: 500 - internal_error: class org.apache.http.conn.HttpHostConnectException - Connect to sfcentral-0002.local:8180 [sfcentral-0002.local/172.16.2.161] failed: Connection refused (Connection refused) (http://sfcentral-0002.local:8180/b2_internal/authorize_account)
 at Duplicati.Library.Main.BackendManager.List () [0x00038] in <118ad25945a24a3991f7b65e7a45ea1e>:0 
 at Duplicati.Library.Main.Operation.FilelistProcessor.RemoteListAnalysis (Duplicati.Library.Main.BackendManager backend, Duplicati.Library.Main.Options options, Duplicati.Library.Main.Database.LocalDatabase database, Duplicati.Library.Main.IBackendWriter log, System.String protectedfile) [0x0000d] in <118ad25945a24a3991f7b65e7a45ea1e>:0 
 at Duplicati.Library.Main.Operation.FilelistProcessor.VerifyRemoteList (Duplicati.Library.Main.BackendManager backend, Duplicati.Library.Main.Options options, Duplicati.Library.Main.Database.LocalDatabase database, Duplicati.Library.Main.IBackendWriter log, System.String protectedfile) [0x00000] in <118ad25945a24a3991f7b65e7a45ea1e>:0 
 at Duplicati.Library.Main.Operation.BackupHandler.PreBackupVerify (Duplicati.Library.Main.BackendManager backend, System.String protectedfile) [0x000fd] in <118ad25945a24a3991f7b65e7a45ea1e>:0 
 at Duplicati.Library.Main.Operation.BackupHandler.Run (System.String[] sources, Duplicati.Library.Utility.IFilter filter) [0x00860] in <118ad25945a24a3991f7b65e7a45ea1e>:0 
 at Duplicati.Library.Main.Controller+<>c__DisplayClass16_0.<Backup>b__0 (Duplicati.Library.Main.BackupResults result) [0x0030f] in <118ad25945a24a3991f7b65e7a45ea1e>:0 
 at Duplicati.Library.Main.Controller.RunAction[T] (T result, System.String[]& paths, Duplicati.Library.Utility.IFilter& filter, System.Action`1[T] method) [0x00072] in <118ad25945a24a3991f7b65e7a45ea1e>:0

I don’t pretend to understand the error but it looks like it’s reporting a back blaze b2 authorization error maybe?
Not sure why it would fail to connect in the middle of a run or how to correct this?

2

Update
After 4 or 5 failures I was finally able to get the backup running again. No changes were made to the backup and I have no idea why it failed in the first place or why it’s working now.