If not, the problem is in the phone cable or phone jack. Fourth, make sure you're using the proper dial commands. Sometimes online, a BBS will report that a file wasn't found. Wrong file extensions are the most common. Don't assume all file extensions are Zip.
Wrong filenames come from reading or typing the name incorrectly.
The most confusing are those names that contain 0's that look like capital O's. If you get a file not found message, double check your spelling. Finally, some files are protected by Sysops. Most notable are recent uploads. Some systems will show you these files, but they cannot be downloaded until the Sysop checks them for virus infestations.