Unable to write a file on Azure Storage

[jakapunlmc]

We would like to write the file and store to Azure Storage but it's error while the read permission is working fine.

I'm pretty sure that we have the right Access Control (IAM) setup on the Azure Portal, the Container is public, and also the Role Assignment is configured. I also wrote the JS script to write a dummy file to the Azure storage, and it's successfully, so it shouldn't be an issue on the Azure side. 

I already dig into the threads in this forum, and also googling, but not found the solution yet.

The 2 below screenshots are to demonstrate that the read one is working fine (1st screenshot) but not the write one (2nd screenshot)