How to fix "401 Unauthorized" error in PUT Invoke-RestMethod (trying to replace stored procedure) - azure

Question

I'm trying to manage CosmosDB resources using REST API and PowerShell.
My code works fine when I use GET and POST, but when I try to replace an existing object using PUT, I get 401 error.
My code registers stored procedure when it doesn't exist and should update it when the SP already exists.
So when I create a new SP, I use the following variables:
$Verb = "POST"
$ResourceType = "sprocs"
$ResourceLink = "dbs/$DBName/colls/$CollName"
$queryUri = "$CosmosDBEndPoint$ResourceLink/$ResourceType"
get auth header:
...
$authHeader = Generate-MasterKeyAuthorizationSignature -verb $Verb -resourceLink $ResourceLink -resourceType $ResourceType -key $MasterKey -keyType "master" -tokenVersion "1.0" -dateTime $dateTime
and then call REST method:
$header = #{authorization=$authHeader;"x-ms-version"="2017-02-22";"x-ms-date"=$dateTime}
$contentType= "application/json"
Invoke-RestMethod -Method $Verb -ContentType $contentType -Uri $queryUri -Headers $header -Body $body
It works great and creates what it should.
And, when I need to replace existing object (SP in my case), I change variables like this:
$Verb = "PUT"
$ResourceType = "sprocs"
$ResourceLink = "dbs/$DBName/colls/$CollName"
$ItemName = "SP_Name"
$queryUri = "$CosmosDBEndPoint$ResourceLink/$ResourceType/$ItemName"
generate auth header just like in case with POST (only verb is different):
...
$authHeader = Generate-MasterKeyAuthorizationSignature -verb $Verb -resourceLink $ResourceLink -resourceType $ResourceType -key $MasterKey -keyType "master" -tokenVersion "1.0" -dateTime $dateTime
...
and the invoke REST method with new URI (which includes now name of SP to be changed):
$header = #{authorization=$authHeader;"x-ms-version"="2017-02-22";"x-ms-date"=$dateTime}
$contentType= "application/json"
Invoke-RestMethod -Method $Verb -ContentType $contentType -Uri $queryUri -Headers $header -Body $body
Which is throws me 401 Unauthorized, so it seems that auth header isn't right. Can't figure out what I should change there.

Answer 1

From here it looks like the resource or the value in the resource you are trying to change does not support a PUT action. You can confirm manually;
https://learn.microsoft.com/en-us/rest/api/cosmos-db/
or by going to;
https://resources.azure.com/

Answer 2

So the key was to change variables this way:
$ResourceType = "sprocs"
$ItemName = "SP_Name"
$ResourceLink = "dbs/$DBName/colls/$CollName/$ResourceType/$ItemName"
and then generate auth header.
I.e. resource link variable must contain the full path to the replaced object.