500 Internal Server Error when rest api call

Hello Everyone,

When i call first rest service . There is no problem .

when i call second rest service. it takes internal 500 error. There is no problem when i call with soap ui or postman.

Error detail.

I think when i add rest services . I am trying to testing. it works. You can see in the picture above.

Is there anyone help me?



Can you enable full logging on your API call and download the HTTP request log file?
Remove sensitive data and if possible, share with us. It will make it easier for us to help you.

How to enable logging:

  1. Go to the Service Center management console of your OutSystems environment;
  2. Go to Factory section and open your application;
  3. Open the module containing your REST API;
  4. Select the Integrations tab and click on the REST API name to edit it;
  5. Set the Logging Level to the value you want;
  6. Click Apply.

Niels F.


Thank you for all reply.

I have added detail.


Hello Ahmet,

Does the web service uses authentication? Like Basic Authentication?

When you expose a rest with basic authentication in OutSystems, the message returned on failed authentication is a 500...


Hello Eduardo,

I have no Authentication at now. 




You didn't SET basic authentication. But if the web service requires it, you need to provide it.

This rest is being exposed aldo by an OutSystems application? The method that works is in the same web service? 

Are you sure you are passing valid values to the input parameter?



I wrote a web services using with c# web api. This web services no need to authentication at now. I am calling this web services from outsystem platform. This web api services connect to sap system. So i am using sap .Net connector on web api. There are lots import and export parameters in SAP. 

Probably  passing invalid values to the input parameters. Sap systems has a TABLES. This tables can import and export. Every tables has more than 100 columns. 

it is not easy to check.

Thank you


Hi Ahmet,

If you wrote the REST service you are calling, then it's your own REST service that produces the 500 and returns this:

So this is not an OutSystems problem, but a problem in your C# code.

That said, may I enquire why you are connecting to SAP through C# code, instead of via OutSystems directly?

Hi Kilian,

When i debug my code on visual studio or When I  call web services with url on postman or soap ui. I have no error both.I wrote more than 20 service in this services. There is no wrong except ones.

We have a plans  that we will call these services from the other applications in the future. Not only outsystems platform. 

I will concantrate parameters.



When i testing . It works. i can get answers.


Hi Ahmet,

Can't you debug the C# code while you are calling from OS? That allows you to see what's going on. Also, as you can see from the debug trace, the only thing you send is a language code:

EDIT: You Ninja'd me with your last post. In there, you send much more than just the language. So you are not passing the right input when calling it from your code. Also, perhaps you can change your C# code so that it sends better error messages than "an error has occured" :).


i will ask questions. I  consume rest api (i have added attachment as jsonTest.txt).

You can give attention ZERO_DISABLE field 

I have added pictures

ORDER_CONDITION_EX has no ZERO_DISABLE field  but program created automatically.



Hi Ahmet,

When consuming a REST API, Service Studio sometimes merges overlapping JSON structures. E.g. when you have something like this:


Service Studio will create a Structure with two Text Attributes named "Item" and "Name". When it encounters another JSON definition like this:


it might well merge the two, and add a "Description" Attribute to the Structure already containing "Item" and "Name". This is pretty annoying sometimes, but that's what SS does, so you should be aware of it.

Hi Ahmet. 

I had the same problem. I got the token and in the second API call, I started receiving the "500 internal server error" one morning. In my case I think was a thing of connection:

I deformed the token and then receive the "401 Unauthorized error". I just corrected the token again and all was solved. As I say, in my case I think was a thing of connection on the server-side.


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