topic MashupException.Error: an error occurred during the pre-login handshake in Dataflow

MashupException.Error: an error occurred during the pre-login handshake

WhisperofCoding — Wed, 05 Jul 2023 09:49:07 GMT

Hi guys,

I keep receiving an error while fetching data with a Dataflow Gen2. I am trying to get data through our Gateway (version 3000.178.9) but keep hitting the same error over and over.

I tried 2 options through the gateway:

- Receiving data from a database on a local SQL server (autorization is correct)

- Receiving data from csv file on our network

Both options gave the same errors.

We also use Power BI through this same gateway without any problems.

I used 'My workspace', but also created a new workspace, still the same problems.

Full error message:

Mashup Exception Error Couldn't refresh the entity because of an issue with the mashup document MashupException.Error: Microsoft SQL: A connection was successfully established with the server, but then an error occurred during the pre-login handshake. (provider: TCP Provider, error: 0 - The semaphore timeout period has expired.) Details: DataSourceKind = Lakehouse;DataSourcePath = Lakehouse;Message = A connection was successfully established with the server, but then an error occurred during the pre-login handshake. (provider: TCP Provider, error: 0 - The semaphore timeout period has expired.);ErrorCode = -2146232060;Number = 121;Class = 20 GatewayObjectId: xxxxxx

Re: MashupException.Error: an error occurred during the pre-login handshake

WhisperofCoding — Wed, 05 Jul 2023 20:27:40 GMT

I also tried the gateway port test, that all came out with status 'Success':

Overall Results : 32/32 tests succeeded.

Re: MashupException.Error: an error occurred during the pre-login handshake

AnthonyGenovese — Thu, 06 Jul 2023 16:22:12 GMT

I am having the same issue. It loads the data from on prem fine. You can see the data in the staging warehouse. However it doesn't write it to the Lakehouse correctly

Re: MashupException.Error: an error occurred during the pre-login handshake

miguel — Thu, 06 Jul 2023 16:42:05 GMT

hey folks! Could you please read the article below and check if these proxy considerations have any impact on your scenarios?

Configure proxy settings for the on-premises data gateway | Microsoft Learn

Re: MashupException.Error: an error occurred during the pre-login handshake

motoray — Thu, 06 Jul 2023 18:27:24 GMT

Having the same issue here. Have tried everything I can think of--rebuilding the workspace and dataflows multiple times. I was able to load data from a Gen1 dataflow source into a Lakehouse, but can't get the onprem data to go from the staging lakehouse into the production lakehouse.

Re: MashupException.Error: an error occurred during the pre-login handshake

SidJay — Fri, 07 Jul 2023 08:05:54 GMT

Could you please confirm that the configuration that Miguel suggested earlier in the thread has been applied?

Configure proxy settings for the on-premises data gateway | Microsoft Learn

Additionally, Port 1433 needs to be opened. The documentation is being updated to include this.

Thanks

Re: MashupException.Error: an error occurred during the pre-login handshake

motoray — Fri, 07 Jul 2023 14:43:09 GMT

Am currently working with my IT folks to try and get that port opened. We'll see what they say.

I thought the whole point of the gateway is so you don't have to jump through these kinds of hoops--it's been pretty great up to now. And I still don't understand why the port needs to be opened if I'm getting data in the staging warehouse--at that point, isn't the next step just moving it from staging to the warehouse?

Re: MashupException.Error: an error occurred during the pre-login handshake

SidJay — Sat, 08 Jul 2023 05:46:25 GMT

When a dataflow is bound to a Gateway, all the read and write operations are executed via the Gateway.

To transfer data from staging to a warehouse without using the Gateway, you would currently need a separate dataflow that is not bound to a Gateway.

Dataflows are either executed entirely in the Cloud or entirely on a Gateway. There isn't a blended mode.

Thanks

Re: MashupException.Error: an error occurred during the pre-login handshake

Joe_Doe — Wed, 09 Apr 2025 01:38:57 GMT

Hi! Has anyone found a solution to this problem? I'm having the same pre-login handshake error for all my Gen2 Dataflows. Gen1 Dataflows work fine. Whether I'm using a lakehouse or a warehouse as the destination, the same thing happens. I've tried many ways to fix this, but to no avail. I opened a support ticket, and they didn't offer any solution. Their response is that it's network glitches. :S

Re: MashupException.Error: an error occurred during the pre-login handshake

Joe_Doe — Wed, 09 Apr 2025 01:39:39 GMT

Re: MashupException.Error: an error occurred during the pre-login handshake

SidJay — Fri, 11 Apr 2025 01:14:22 GMT

If you're using a Gateway could you please verify that port 1433 is open.

More details:
On-premises data gateway considerations for data destinations in Dataflow Gen2 - Microsoft Fabric | Microsoft Learn

Thanks