The API call in the Domino Mail Service - http://{host}/api/mail returns an array of folders (links).
The last element in that array is followed by a comma:
{
"mailboxes":[
{
"owner":{
"displayName":"Duke Lawson",
"distinguishedName":"Duke Lawson\/Peaks",
"email":"DukeLawson@swg.usma.ibm.com"
},
"links":[
{
"rel":"inbox",
"href":"http:\/\/server.xyz.com\/mail\/dlawson.nsf\/api\/mail\/inbox"
},
{
"rel":"outbox",
"href":"http:\/\/server.xyz.com\/mail\/dlawson.nsf\/api\/mail\/outbox"
},
{
"rel":"sent",
"href":"http:\/\/server.xyz.com\/mail\/dlawson.nsf\/api\/mail\/sent"
},
{
"rel":"drafts",
"href":"http:\/\/server.xyz.com\/mail\/dlawson.nsf\/api\/mail\/drafts"
}, <<<<<<< PROBLEM HERE
]
}
]
}
This breaks the JSON and means it cannot be parsed.