CouchDB replication - Unauthorized to access or create database

I am trying to setup a CouchDB database replication but both is not working via Futon and cURL/CLI: It ends up with the following error message in both cases:

{"error":"unauthorized","reason":"unauthorized to access or create database table1"}

curl -X POST http://127.0.0.1:5984/_replicate -d '{"source": "table1",
"user_ctx": {"name": "", "roles": ["admin"]}, "target":   
"http://username:password@server:5984/table1", "create_target": false, 
"continuous": true}' -H "Content-Type: application/json"

The target database is secured via a username and password and for HTTP basic authentication i added the credentials as you can see. The same error appears when i create a replication document via Futon.

Thanks for your help.