Updating value from one custom module to another

Hi,

I have 2 modules :

Offre GC (tab) called Custommodule1 (name) and API : Name Offer
Société (tab) called Accounts (name) and API : Name Accounts

I have a field called "Gardiennage" (and many others, but we will start with one and I will duplicate ;-)), and I would like to update this field on my "Sociétés" module when field is updated on "Offre GC".

I've tried to use and adapt this code but it isn't working :

ARGUMENT

CustommoduleId = ID Offre GC

CODE

CustommoduleDetails = zoho.crm.getRecordById("Offer",CustommoduleId.toLong());

createMap = Map();

createMap.put("Gardiennage",ifnull(CustommoduleDetails.get("Gardiennage"),""));

createCustomModule = zoho.crm.createRecord("Accounts",createMap);

info createMap;

info createCustomModule;

I've checked datas: it works fine, my fields have the same name, api find module, so it's ok.

I tried to work with an example I got this message :

{"Gardiennage":"Non"}

{"code":"MANDATORY_NOT_FOUND","details":{"api_name":"Account_Name"},"message":"required field not found","status":"error"}

What does it mean ?

Thanks for your help,