Every time an admin tries to log in, he/she receives an error that the "User Name or Password is Invalid". The admin then goes through the password reset process and is able to log in.
When you see the user name/password error, check the URL. Make sure the URL is not https://secure2.convio.net/[site]/admin/ConvioLoginor https://secure2.convio.net/cnv/admin/AdminLogin. Those URLs will not work for any non-Blackbaud employees. If you are using one of those URLs to log in, check with another admin in your organization to find out what the correct login URL should be, or you can use this guide to find your Luminate administrator login URL (BB744809).
Alternatively, you can Contact Support and reference this article. Support can provide you with the correct URL to log in.