@ watrworld - If you're confident all is well with your iMsg configurations, to prove this, try with a family member or friend's Apple login account and see. If logon is successful then all is well, it just means your Apple ID has thrown up a security flag on your rig for a period of time so just sit back for the time being and refrain from changing S/N or any other injected value as this will only exasperate the problem more. Resist the urge of constant trying to logon for a few days, other members with the exact problem found after some weeks even months the block was cleared. Good luck.