Time Capsule Internet problems

Since setting up my Time Capsule a few weeks ago, I have had constant trouble with my internet. I use two different secure email clients through the Mail app and both of them don't work more than they do work. "Server not responding" or "server not available" are among the messages I get. What's more, I am commonly unable to load websites because "Safari can't find the server." Also, at times a page will load in a "crude" form, with wrong formatting and no pictures, but with all the text that should be displayed. I bet all these issues are from a single source problem, but can't figure out what that would be.

Any help would be appreciated!