Jira Backup using REST API

[Niraj Lathiya]

Using below code we use to take backup for quite a long however now it's not longer working I tried reading documentations and community discussion but couldn't find subsential solution I am getting error 

Error :  You cannot call a method on a null-valued expression.
At line:56 char:9
+ $InitiateBackup = $_.Exception.Response.GetResponseStream()
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (:) [], RuntimeException
+ FullyQualifiedErrorId : InvokeMethodOnNull



[System.Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

if(!(Test-Path -path $destination)){
write-host "Folder is not present, creating folder"
mkdir $destination #Make the path and folder is not present
}
else{
write-host "Path is already present"
}

#Convert credentials to base64 for REST API header
function ConvertTo-Base64($string) {
$bytes = [System.Text.Encoding]::UTF8.GetBytes($string);
$encoded = [System.Convert]::ToBase64String($bytes);
return $encoded;
}

$b64 = ConvertTo-Base64($username + ":" + $token);
$auth = $b64;

$string = "cbAttachments:true, exportToCloud:true"
$stringbinary = [system.Text.Encoding]::Default.GetBytes($String) | %{[System.Convert]::ToString($_,2).PadLeft(8,'0') }

$body = @{
cbAttachments=$attachments
exportToCloud=$cloud
}
$bodyjson = $body | ConvertTo-Json

if ($PSVersionTable.PSVersion.Major -lt 4) {
throw "Script requires at least PowerShell version 4. Get it here: https://www.microsoft.com/en-us/download/details.aspx?id=40855"
}

# Create header for authentication
[string]$ContentType = "application/json"
[string]$URI = "https://$account.atlassian.net/rest/backup/1/export/runbackup"

#Create Header
$header = @{
"Authorization" = "Basic "+$auth
"Content-Type"="application/json"
}

# Request backup
try {
$InitiateBackup = Invoke-RestMethod -Method Post -Headers $header -Uri $URI -ContentType $ContentType -Body $bodyjson -Verbose | ConvertTo-Json -Compress | Out-Null
} catch {
$InitiateBackup = $_.Exception.Response.GetResponseStream()
$reader = New-Object System.IO.StreamReader($InitiateBackup)
$reader.BaseStream.Position = 0
$reader.DiscardBufferedData()
$responseBody = $reader.ReadToEnd();
}

$responseBody

$GetBackupID = Invoke-WebRequest -Method Get -Headers $header https://$account.atlassian.net/rest/backup/1/export/lastTaskId
$LatestBackupID = $GetBackupID.content

# Wait for backup to finish
do {
$status = Invoke-RestMethod -Method Get -Headers $header -Uri "https://$account.atlassian.net/rest/backup/1/export/getProgress?taskId=$LatestBackupID"
$statusoutput = $status.result
$separator = ","
$option = [System.StringSplitOptions]::None
$s

if ($status.progress -match "(\d+)") {
$percentage = $Matches[1]
if ([int]$percentage -gt 100) {
$percentage = "100"
}
Write-Progress -Activity 'Creating backup' -Status $status.progress -PercentComplete $percentage
}
Start-Sleep -Seconds 5
} while($status.status -ne 'Success')

# Download
if ([bool]($status.PSObject.Properties.Name -match "failedMessage")) {
throw $status.failedMessage
}

$BackupDetails = $status.result
$BackupURI = "https://$account.atlassian.net/plugins/servlet/$BackupDetails"

[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]"tls12, tls11, tls"
$i=1;
$tries=5;
$worked = $false
while((-not $worked) -and ($i -le $tries))
{
try {
write-host "Download starting"
Invoke-WebRequest -Method Get -Headers $header -WebSession $session -Uri $BackupURI -OutFile (Join-Path -Path $destination -ChildPath "JIRA-backup.zip")
write-host "Download completed"
$worked = $true
} catch [Exception] {
echo $_.Exception.GetType().FullName, $_.Exception.Message
$i=$i+1;
}
}

[Niraj Lathiya]

I've attempted to use alternative methods from here https://bitbucket.org/atlassianlabs/automatic-cloud-backup/src/master/, but I'm receiving a 401 error. I've double-checked that the username and API token are correct.