Connect LDAP library from Vault with Boundary

I’m configuring my first boundary and vault servers. I was able to configure Boundary, add Azure for authenticating users, add targets to it etc.
Now I’m trying to connect Vault to it.
I was able to connect Vault successfully but when I try to add the ldap secrets engine to it (connected to an AD server), it doesn’t seem to be able to retrieve the username and password when I attach it to a target. If I do it directly via cli Vault does give me the info so I know the connection from Vault to my AD Server is working.
I used the Service Account Check-Out option with LDAP.

When I try to connect a target I get this error message :

targets.(Service).AuthorizeSession: vault.(Repository).Issue: vault.(client).post: vault: external system issue: error #3014: Error making API request. URL: PUT Code: 400. Errors: * error parsing JSON

I tried a Get and a Post in the Credentials Library in Boundary but I don’t get same error message so I presume I need to use a POST to get the credentials?

This is the POST I have in Boundary right now :

–header “X-Vault-Token: …”
–request POST
–data @payload.json

The checkout function of the LDAP secrets engine might need some additional customization to work, if it works at all. By default Boundary wants to just do a GET on the secret endpoint, which works with a variety of secrets engines like K/V or the database secrets engine. It can do a POST but you then have to define a JSON body to send in the request, and I think that’s where things are failing – the Vault error you get is about a failure to successfully decode that JSON body.

Are you able to submit that same JSON request body to the Vault secret API endpoint with curl and get a response back with service account info?