Are there specific invalid characters for usernames or passwords when connecting to Milestone through the API?

We are having difficulties connecting one of our clients through the API integration and were wondering if some of the characters they use for passwords or usernames are causing issues.

The integration/authentication appears to work fine when using a Local (admin-level) Milestone account, but not when using a Windows Authentication Account (also assigned Admin-level privileges). We are wondering if this could be because:

  1. The Windows Account they are using is a domain account which requires the domain plus backslash (is the backslash an illegal character in the authentication string? Domain\Username)
  2. The password they use for this Windows account has several symbol/special characters in it (specifically @, $, % and &). Are any of these symbols/characters illegal characters in passing through the password via the API?

Thank you,

We do not think the issue is about illegal characters, we would answer no to the questions.

Could you share code to show what you do? Please also share if there are any relevant log messages in the log files when the login fails.