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Adding new element to BC Custom Table through BC Custom API using C#

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Posted on by VR-01091303-0

HI,

I have an application that needs to interact with BC.

For that purpose, I am using Azure function that will query BC.

I have already created a custom table + custom API.

Am able to fetch data, update data, but cannot insert new record.

I have already set the permission to the tabledata as RIMD.

However, creating record through postman works well, but in c#, it is giving me permission error.

I would like to know if there are any means or anything that I have missed.

In C#, I tried both through odata class and direct raw posting. but none is working.

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Dynamics 365 Business Central

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Dhiren Nagar 2,876 Super User 2026 Season 1 on at

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Hi,

I hope you are using App Registration in Azure for connecting with BC.

If yes, make sure that through Azure function and postman you are using same credentials.

Also check the permission for App user in BC.

Regards,

Dhiren.

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Khushbu Rajvi. 21,573 Super User 2026 Season 1 on at

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Can you share the exact error message?

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OussamaSabbouh 11,500 Super User 2026 Season 1 on at

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Hello,

Nothing is wrong with your table permissions: Permissions = tabledata = RIMD only applies to AL code running inside BC, not to external API calls. Your issue is almost certainly authentication context—Postman usually works because it uses a delegated user token (your BC user already has permission sets), while your C# Azure Function likely uses client-credentials (app-only) auth, which BC treats as a separate identity with no permission sets by default. You must add the Entra App Registration into Business Central and assign it permission sets (or SUPER temporarily to confirm), ensure the token scope is https://api.businesscentral.dynamics.com/.default, and then POST will work; the fastest proof is to reuse the exact same access token from Postman in C# and see it succeed.

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YUN ZHU 98,311 Super User 2026 Season 1 on at

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This is clearly a problem with OAuth 2.0 authentication processing in C#.
Hopefully, the following information will give you some hitns.

Can we get all environments within BC via AL (Not in Admin Center)

https://yzhums.com/61528/

Thanks.

ZHU

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