If you can access your email account from other computers then the issue has to bee some security software on your computer. If the block was put on Comcast’s end you would not bee able to access it on any computer. It is possible you have some parental controls on your computer or other security software that your email address has been entered in as something that should bee blocked. Assuming you are using a windows operating system if you run your mouse over the icons on the lower right hand side of your screen by your clock, you should bee able to see what security software you have. If you disable the software then try logging in it should resolve the issue. If you are unable to disable the software or if you do disable it and the issue is unresolved, they I would reset the browser by going to the reset button on the advanced tab, press apply then ok. Close Internet Explorer and reopen it and try clogging in. If you are using a Mac in safari under the safari menu there is an option that states reset safari. If nun of the above steps has resolved your issue you will need to consult with a computer technician to resolve the problem.