CFDs are not available in the USA due to local regulation and regulated brokers do not accept US citizens or US residents as clients.
Retry logging into your MT4 account, it's possible you made a typo on your account number (username) or password.
A VFSC license or "Vanuatu Financial Services Commission License" gives brokers access to uncapped leverage. In addition, brokers can act as an STP broker or a market maker. The VFSC allows PAM/MAMM accounts as well as money management services.
Eightcap leverage starts at 100:1 and goes up to a maximum of 500:1.
Click on the little gear icon in user settings (lower left of the screen), click on Notifications on the left menu, scroll down and turn "Message" off. Done.
Yes, you can get a GO Markets demo account with $50,000 in virtual money to trade with, for free using GO Markets servers to test out their trading services.
Admiral Markets is the well-reputed brokerage firm established in 2001.