Avivos error after completing backup duplicati Ubuntu 16.04

I am having these warnings in a backup in Ubuntu 16.04
The duplicati version is however I have others running on that version without these warnings.
This backup is being saved via ssh protocol on another linux server
I’ve reviewed the routine but I’m not finding the cause
thank you

Log data:
2018-09-30 03:48:19 -03 - [Warning-Duplicati.Library.Modules.Builtin.ReportHelper-ReportSubmitError]: Failed to send message: System.Net.WebException: Value cannot be null.
Parameter name: src
–> System.ArgumentNullException: Value cannot be null.
Parameter name: src

System.Net.WebException: Value cannot be null.
Parameter name: src —> System.ArgumentNullException: Value cannot be null.
Parameter name: src
at System.Buffer.BlockCopy (System.Array src, System.Int32 srcOffset, System.Array dst, System.Int32 dstOffset, System.Int32 count) [0x00003] in <2943701620b54f86b436d3ffad010412>:0
at System.Net.WebResponseStream+d__49.MoveNext () [0x00082] in :0
— End of inner exception stack trace —
at System.Net.HttpWebRequest+d__244`1[T].MoveNext () [0x000c5] in :0
— End of stack trace from previous location where exception was thrown —
at System.Net.WebConnectionStream.Read (System.Byte buffer, System.Int32 offset, System.Int32 count) [0x00077] in :0
at System.IO.StreamReader.ReadBuffer () [0x00028] in <2943701620b54f86b436d3ffad010412>:0
at System.IO.StreamReader.ReadToEnd () [0x00052] in <2943701620b54f86b436d3ffad010412>:0
at Duplicati.Library.Modules.Builtin.SendHttpMessage.SendMessage (System.String subject, System.String body) [0x0019b] in :0
at Duplicati.Library.Modules.Builtin.ReportHelper.OnFinish (System.Object result) [0x00138] in :0

WebResponseStream might be code in Mono choking on something the web server responded with to the Duplicati http report that runs after the backup is done. Do all the systems have this set up the same way?

C:\Program Files\Duplicati 2>Duplicati.CommandLine.exe help sendhttp
HTTP report module (sendhttp):
 This module provides support for sending status reports via HTTP messages
 Module is loaded automatically, use --disable-module to prevent this
 Supported options:
  --send-http-url (String): HTTP report url
    HTTP report url
  --send-http-message (String): The message template
    This value can be a filename. If the file exists, the file contents will
    be used as the message.

In the message, certain tokens are
%OPERATIONNAME% - The name of the operation, normally
%REMOTEURL% - Remote server url
%LOCALPATH% - The path to the
    local files or folders involved in the operation (if any)
    - The parsed result, if the operation is a backup. Possible values are:
    Error, Warning, Success

All command line options are also reported
    within %value%, e.g. %volsize%. Any unknown/unset value is removed.
    * default value: Duplicati %OPERATIONNAME% report for

  --send-http-message-parameter-name (String): The name of the parameter to
    send the message as
    The name of the parameter to send the message as.
    * default value: message
  --send-http-extra-parameters (String): Extra parameters to add to the http
    Extra parameters to add to the http message. I.e.
  --send-http-level (Enumeration): The messages to send
    You can specify one of "Success", "Warning", "Error", "Fatal".
You can
    supply multiple options with a comma separator, e.g. "Success,Warning".
    The special value "All" is a shorthand for "Success,Warning,Error,Fatal"
    and will cause all backup operations to send a message.
    * values: Unknown, Success, Warning, Error, Fatal, All
    * default value: all
  --send-http-any-operation (Boolean): Send messages for all operations
    By default, messages will only be sent after a Backup operation. Use this
    option to send messages for all operations
  --send-http-verb (String): Sets the HTTP verb to use
    Use this option to change the default HTTP verb used to submit a report
    * default value: POST
  --send-http-log-level (Enumeration): Defines a log level for messages
    Use this option to set the log level for messages to include in the report
    * values: ExplicitOnly, Profiling, Verbose, Retry, Information, DryRun,
    Warning, Error
    * default value: Warning
  --send-http-log-filter (String): Log message filter
    Use this option to set a filter expression that defines what options are
    included in the report
  --send-http-max-log-lines (Integer): Limits log lines
    Use this option to set the maximum number of log lines to include in the
    report. Zero or negative values means unlimited.
    * default value: 100
  --send-http-result-output-format (Enumeration): Selects the output format
    for results
    Selects the output format for results. Available formats: Duplicati, Json
    * values: Duplicati, Json
    * default value: Duplicati

C:\Program Files\Duplicati 2>

To see what’s in the http report (in case it matters), you could try sending a similar report using email instead. Also possible is that the web server you send to will have some log of what came in, or what error was sent…

There’s also a chance you’ll have more Duplicati information if you increase the log level, e.g. to Information, however it’s also possible that things are upset enough that they can only throw that exception, and no more.