We’re running into a persistent 401 Unauthorized error when trying to POST inventory transactions through the REST API. Our OAuth2 client credentials are configured correctly in the API Gateway, and we’ve verified user roles and scopes multiple times in the security console. The same credentials work fine for GET requests to retrieve inventory data, but any POST or PUT operation fails immediately.
Here’s the error we’re getting:
HTTP/1.1 401 Unauthorized
WWW-Authenticate: Bearer error="invalid_token"
{"error":"insufficient_scope","error_description":"Token lacks required scope"}
Our OAuth2 token request includes scope=“inventory.write” and we’ve confirmed this scope is assigned to our service account. The API Gateway logs show the token is validated successfully, but something breaks during the authorization phase. Has anyone dealt with scope validation issues in ICS 2021 when using the API Gateway for inventory operations?
Thanks for the suggestions. I checked the scope mapping and it looks correct. I’ll try adding the read scope as well, though that seems odd. One thing I noticed - when I look at the decoded JWT token, the ‘aud’ (audience) claim shows our gateway URL but the ‘scope’ claim only lists ‘inventory.write’. Could this be a token generation issue rather than a gateway configuration problem?
Check if your API Gateway has the scope mapping configured correctly for inventory write operations. In ICS 2021, there’s sometimes a mismatch between the OAuth2 scope names and the actual permission mappings in the gateway. Go to API Gateway Admin > Security Policies and verify that ‘inventory.write’ is mapped to the correct backend permissions.
I’ve seen this before. The issue might be that you need BOTH ‘inventory.write’ and ‘inventory.read’ scopes in your token request. ICS 2021 API Gateway sometimes requires read permissions even for write operations because it validates the resource exists first. Try requesting scope=“inventory.read inventory.write” in your OAuth2 client credentials flow. Also double-check that your client ID has been granted these scopes in the OAuth2 provider configuration - sometimes the scopes are assigned to the user but not to the client application itself.
Another thing to verify - are you using the correct grant type? For server-to-server inventory transactions, you should be using ‘client_credentials’ grant type. If you’re accidentally using ‘authorization_code’ or another flow, the token won’t have the right claims structure. Also, make sure your token hasn’t expired - ICS 2021 default token lifetime is 3600 seconds but some admins shorten it to 1800 for security.
I had almost the exact same issue last month. Here’s what fixed it - you need to check THREE specific areas where OAuth2 configuration can break:
1. OAuth2 Client Credentials Configuration:
Verify in your OAuth2 provider that the client has been granted BOTH scopes explicitly. In ICS 2021, go to Security Console > OAuth2 Clients > [Your Client] > Allowed Scopes. You should see both ‘inventory.read’ and ‘inventory.write’ checked. The system requires read permission to validate the inventory location exists before allowing writes.
2. API Gateway Authorization Mapping:
The gateway needs explicit permission mapping. Navigate to API Gateway Admin > Security Policies > Scope Mappings. Create or verify these mappings:
inventory.write -> INV_TRANSACTION_CREATE
inventory.write -> INV_TRANSACTION_UPDATE
inventory.read -> INV_TRANSACTION_READ
3. User Role and Backend Permissions:
This is the part most people miss - even with correct OAuth2 scopes, the service account user must have the actual ICS security roles assigned. Go to User Management > Service Accounts > [Your Service Account] and verify these roles are assigned:
- Inventory Transaction Manager
- Inventory Data Reader
The 401 error with ‘insufficient_scope’ usually means step 2 is misconfigured. The API Gateway is successfully validating your token but can’t map the OAuth2 scope to the required backend permission. After fixing the scope mappings, restart the API Gateway service to clear any cached authorization policies.
One more thing - if you’re posting transactions with specific warehouse or location codes, make sure your service account has data-level security permissions for those locations. ICS 2021 enforces location-based access control even through APIs, so a valid token with correct scopes can still fail if the user doesn’t have access to the specific inventory location in the transaction payload.
Test your fix with a simple curl command:
curl -X POST https://your-gateway/api/inventory/transactions \
-H "Authorization: Bearer YOUR_TOKEN" \
-H "Content-Type: application/json" \
-d '{"location":"WH01","item":"ITEM001","quantity":10}'
If this works, your OAuth2 and gateway configuration is correct and any remaining issues are likely data-level permissions.