You are running a repotools command and get an error similar to:
CRJAZ1357E Failed to login into the server 'https://<serverName>:9443/jts'.
Check the login credentials.
The repotools command may require credentials.
Resolving the problem
Run the repotools command -help on the server to see the full set of parameters for any given command. The Information Center documentation links for repotools commands do not always list the credentials parameters.
Here is the Information Center reference for commands:
Repository tools command-line reference
In some cases, the credentials parameters are not listed. But by using repotools-jts.bat -help on the server, you will see all parameters.
The Jazz based products have an active community that can provide you with additional resources. Browse and contribute to the User forums, contribute to the Team Blog and review the Team wiki.