SFTP - SSH (BadGateway) Error

[MicahBrewer123]

Hello. 

I have a very simple flow but I'm getting a badgateway error. 

Flow

1. Get an Email Attachment from the specified shared mailbox.
2. Save email to SFTP.

The error I'm getting is not helpful, so perhaps there is some way to view a more detailed error.

So here's the background. The SFTP I'm trying to hit is a customer-owned SFTP. They recently updated their public IP, but I'm not using the IP, I'm using DNS, so I don't think that would impact me. 

I can hook this same process to another SFTP server and it runs successfully within one sec of receiving the email. That said, I think it is an issue on the SFTP side of things but don't have enough info to tell them what the issue is. I can hit their SFTP with Filezilla and WinSCP. I've tried to use the new IP with no success. 

Any thoughts on what the issue might be but possibly easier to answer, any direction on finding more detail on the actual error?

Thanks all!

[PhilipTreacy]

Hi @MicahBrewer123 

I'm not entirely clear on whether you've successfully used their new IP address to access their SFTP. I'm assuming you are accessing this SFTP server from the public side of their network?

You said that:

I can hit their SFTP with Filezilla and WinSCP.  What IP address did you use?

I've tried to use the new IP with no success. Using what program?  The flow? You just said you could hit their SFTP using FileZilla and WinSCP.

Have you confirmed that DNS returns the correct, new IP address?

A bad gateway error can be misleading sometimes.  But it usually indicates an invalid response was received by a server you were communicating with.  Could just be that whatever IP address you are trying to connect to did not respond as PA expected an SFTP server should.

regards

Phil

[MicahBrewer123]

Hi @PhilipTreacy. Thank you for the response!

To try to be more clear. I have accessed the SFTP with Filezilla and WinSCP using both the new IP and the DNS, which is returning the new IP when I ping it. That said, when I connect using the IP, I get an unknown server warning (below image from WinSCP.

Once I saw this, I thought perhaps the reason PA isn't connecting is because of this warning, so I took the MD5 value and dropped it in the SSH host key finger-print but no change. My SFTP-SHH configuration is below.

Name: Client SFTP

Host: ftp2@somehost.com

Username: myusername

Password: j1g**************

SSH Private Key: disabled

SSH Private Key Passphrase: disabled

Port: 22

SSH host key finger-print: bb:60:04:**:**:**:**:**:**:**:**:**:**:**:**:**

Root folder path: /

Thanks again for your help!

Micah

[MicahBrewer123]

After writing this and posting it, I decided (since I don't know all that much about host key finger-prints, to change from the MD5 value to the SHA-256 (DCjoM***) value. Also no luck. Do I need to somehow "declare" the "ssh-rsa 2048" algorithm in PA? Something like "ssh-rsa 2048 DCjoM*****"?

I'm just guessing at this point. Thanks.

[PhilipTreacy]

Hi @MicahBrewer123 

The warning about the unknown server just means that it thinks it has never connected to that server before, and hasn't stored the server's host key in its cache.  This is a normal message to get if you've never connected to a server before, or stored its host key.

You can Disable SSH host key validation if you are sure you know what server you are connecting to.

In your screen shot you have SSH Private Key and SSH Private key Passphrase marked as disabled.  Shouldn't these be enabled if you are using SSH?  Otherwise you are just using normal non-encrypted FTP?

Have you got the server's Private Key and Passphrase?

Regards

Phil

[MicahBrewer123]

Since SSH Private Key and SSH Private key Passphrase are not marked as required, my assumption was that they are not required. Perhaps the ability to only use username and password is the reason the deprecated SFTP connection was deprecated, because I can use this in the same way.  That said, I'm able to connect to other SFTPs only using u/p. I can try getting SSH info from server host and see if that helps.

I would love for this to be a simple 'lack of knowledge' issue on my part.

Thanks,

Micah

[spr00]

Same issue here.  I can connect using the basic FTP connector, but the SFTP-SSH connector just hangs and reports 'BadGateway'.   I'm supplying known user creds with know additional keys. WinSCP connects fine this way.  Tried assorted syntax and folders for root folder.   It just doesnt work. 

[benzo]

Has anyone had any luck solving this?  I'm facing a similar issue, I can connect from bash using SSH, I have an very similar set up on a different virtual machine, but I just can't get SFTP-SSH to work.

[chadders]

Had this issue recently and solved by changing the type of ssh key I used, turns out certain formats are not supported by power automate.

I had generated with "ssh-keygen" command and it didnt work, generated again with "ssh-keygen -m PEM" and it worked.

[martynaj]

Hi, I am having a similar problem and I see that perhaps there are some solutions here so how is the final screen of Power Automate connector supposed to look like based on Micah's example

[benzo]

I was unable to get Power Automate's SFTP to working in a stable manner.  Instead, I've moved on to use other Azure services such as blob accounts with managed identities (when under the same tenancy) or connection strings, or connecting to Sharepoint etc via the Sharepoint or Graph APIs.  I've found these solutions to be reliable and stable.