"Invalid_Grant" error while calling M3 ION API from Dot Net application.

Hello Team,

I have a requirement to call M3 API's through Dot Net application. While exploring, I found the GitHub library and was trying executing the sample application "DotNetWebClientOAuth2".

Now while executing the program I am able to get the access token successfully but while calling the API I am getting "Invalid_Grant" issue as below -

From the code, I can see that request owner grant is called and I am using backend user IONAPI file.

I tried the same credentials in Postman and was able to get the access token and response from M3 API.

Can somebody help me to figure out the issue or if any changes are required in the code?

Thanks,

Yogesh

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Comments

Kevin Heiman

Can you clarify if this is Cloud or on-premise?

In both cases we would expect APIs to be called from API Gateway and use the authentication mechanics there. Have you considered using API gateway?

Kevin Heiman

Yogesh, in re-reading your topic, I see a little more detail in there than I initially read.

It appears you have a windows application , possibly a Web site or a mobile, that you want to call an Infor API. If the user is going to be present and key in thier credentials then the grant type seem appropriate. What ION API (.ionapi) file parts are you using / mapping ?

Are not getting prompted for credentials?

Can you share the modified code you are working with? or is is straight up the same as the download?

IF you are not intending the user to be present, and want to do machine to machine API calls with impersonization or not... you would use Password credentials grant. I will do more research depending on your replies.

I am aware of several other customers that have used this client code sample successfully. I could also provide a python version of a Machine To Machine that you could validate with. Thanks

Kevin Heiman

adding link to grant types in ION API documentation.

cleverly

Yogesh,

I can't speak to the sample DotNet application, but reviewing this Infor Technology video, How to call an ION API? on YouTube might help.

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