Unable to connect to PRTG Server

[mviveki]

When trying to connect to the PRTG Server using below PS commands.

PS C:\WINDOWS\system32> $cred = Get-Credential
Connect-PrtgServer -Server "servername" -Credential $cred

below Error occurs.

Connect-PrtgServer : The underlying connection was closed: An unexpected error occurred on a send.
At line:2 char:1

• Connect-PrtgServer -Server "servername" -Credential $cred

•   + CategoryInfo          : NotSpecified: (:) [Connect-PrtgServer], WebException
    + FullyQualifiedErrorId : System.Net.WebException,PrtgAPI.PowerShell.Cmdlets.ConnectPrtgServer
  
  

Also use the -IgnoreSSL parameter along with the syntax and also used below command before running the connec-prtg syntax.

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

Note: I used Windows Domain credentials as well as PRTG Passhash.

[lordmilko]

What happens if you try and authenticate using your web browser?

https://prtg.example.com/api/getpasshash.htm?password=prtgadmin&username=prtgadmin

If you change the server from prtg.example.com to whatever your server name is, it should respond with your passhash

Something else to consider is if your server requires TLS 1.3, forcing it to TLS 1.2 means you just lost 1.3 support. It's better to use -bor

[Net.ServicePointManager]::SecurityProtocol = [Net.ServicePointManager]::SecurityProtocol -bor [Net.SecurityProtocolType]::Tls12

Another consideration is maybe instead you might need to add in Tls13 support here. This is a problem you'll mainly have on Windows PowerShell (because .NET Framework does not default to using TLS 1.2+ on some systems). TLS should already be correct in PowerShell Core

[mviveki]

It seems to have connected to the PRTG Server after using below

$cred = New-Credential "username" "passhash"
Connect-PrtgServer -IgnoreSSL -Server "http://prtgserver" -Credential $cred -PassHash -Force

However, when I run further commands e.g. Get-Sensor | Get-Trigger , I again get authentication error.

PS C:\WINDOWS\system32> Get-Sensor | Get-Trigger
Get-Sensor : Could not authenticate to PRTG; the specified username and password were invalid.
At line:1 char:1

• Get-Sensor | Get-Trigger

•   + CategoryInfo          : NotSpecified: (:) [Get-Sensor], HttpRequestException
    + FullyQualifiedErrorId : System.Net.Http.HttpRequestException,PrtgAPI.PowerShell.Cmdlets.GetSensor
  
  

Note: I can run API queries using Web Browser so access is not an issue.

[lordmilko]

Specifying -PassHash skips the API request that resolves the password into the passhash

Can you advise whether your PRTG is running on a custom port? Does it work when you run PrtgAPI locally on the PRTG server? Are you using Windows PowerShell or PowerShell Core?

[mviveki]

No Custom Port. I refrain trying to run locally on PRTG Server. I am using Windows 11 PC and Windows Powershell ISE.

[lordmilko]

Do you use a proxy?

What happens if you try and invoke a PRTG API request directly using PowerShell

Invoke-RestMethod "https://prtg.example.com/api/getpasshash.htm?password=prtgadmin&username=prtgadmin"

[mviveki]

Do you use a proxy?

Yes, I use a Proxy, but tried disabling it as well.

What happens if you try and invoke a PRTG API request directly using PowerShell

Invoke-RestMethod "https://prtg.example.com/api/getpasshash.htm?password=prtgadmin&username=prtgadmin"

Below is the output

PS C:\WINDOWS\system32> Invoke-RestMethod "https:///api/getpasshash.htm?username=username&password="passhash"
The string is missing the terminator: ".
+ CategoryInfo : ParserError: (:) [], ParentContainsErrorRecordException
+ FullyQualifiedErrorId : TerminatorExpectedAtEndOfString

[lordmilko]

You've got an extra quote prior to the passhash

[mviveki]

The result is the same, previously it was a type in reply.

PS C:\WINDOWS\system32> Invoke-RestMethod "https://prtgserver/api/getpasshash.htm?username=username&password=passhash"

Invoke-RestMethod : The underlying connection was closed: An unexpected error occurred on a send.
At line:1 char:1

• Invoke-RestMethod "https://prtgserver/api/getpasshash.htm?username=a ...

•   + CategoryInfo          : InvalidOperation: (System.Net.HttpWebRequest:HttpWebRequest) [Invoke-RestMethod], WebException
    + FullyQualifiedErrorId : WebCmdletWebResponseException,Microsoft.PowerShell.Commands.InvokeRestMethodCommand
  

[lordmilko]

Hi @mviveki,

This is what I expected; this indicates there is some sort of networking issue outside of PrtgAPI. I would recommend testing running this command directly from the PRTG server itself, or on a different computer. The fact you use a proxy is an additional complicating factor here (even though you said you tried disabling it above)

Potentially there may be an inner exception that provides more information about what went wrong. You can access the last exception that was thrown by doing

$error[0].Exception

and can potentially access any inner exception via

$error[0].Exception.InnerException