iControl REST returning 401 on PATCH to ASM policy

Hello,

So I am doing the following steps in Java on 12.1.2;

• receive token
• get ASM policy (using id) in json
• change something in this json, in this example it's changing the description
• Do a PATCH of the exact same object to mgmt/tm/asm/policies/$id

The last step returns a 401. Anyone an idea why? It's not bad credentials, because the token works for retrieving the ASM policy.

restjavad log:

[ForwarderPassThroughWorker]{"user":"tmos/username","method":"PATCH","uri":"http://localhost:8100/mgmt/tm/asm/policies/xxx?ver=12.1.2","status":401,"from":"xxx.xxx.xxx.xxx"}