Hi Huang Heng, (Heng.Huang@partner.bmwgroup.com) •,
Welcome to Microsoft Q&A forum.
As I understand, you are getting Invalid Key error in Azure Database Cosmos MongoDB.
Please take at a look at the post below which shares Invalid key issue solution:
https://blog.velingeorgiev.com/azure-cosmos-db-mongonetworkerror-when-local-development
Let us know if this helps.
If not, please explain on what you are trying to perform on the Azure Cosmos Mongo DB so that we can assist more.
Thanks