After installing the Excel Add-in for Rally the user opens the connection dialog box and enters the appropriate information but there are no function buttons at the bottom of the screen. Buttons on the bottom are missing.
The user likely has a newer unsupported version of Excel, in this case MS Office, Excel 2016 is installed.
The user will have to downgrade his version or enter the correct connection information and in order to connect simply hit the 'Enter/Return' key which is the default action for this dialog box. The user can then use the Add-in until the newer version is supported.