My customers can't login to them accounts when use IP address by FTP software.
What is the problem please?
Thanks

Well, that depends. Were they assigned an IP when their account was set up? Do they get any error messages? Are they using the right username and password? The more information you can provide, and the more troubleshooting steps you have done yourself, the easier it is to get to the root of a problem.

In addition to what Annette said, start from the beginning. Make sure they have FTP permissions.

Assume nothing, check everything.

Were they assigned an IP when their account was set up? YES.
Do they get any error messages? NO.
Are they using the right username and password? YES


Make sure they have FTP permissions.
What steps to Make sure?

Thanks