Ok, I've disabled the so called "Stronghold" cookie which checks your location everytime to access the website. Any change to the location (Possibly caused when shutting it off, or after time, depending on your service provider), would cause you to have to log back in. Please tell me if this makes any difference
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Create a stronghold auto-log in cookie?
If enabled, when a member logs in, an additional cookie is set which contains geographic information in a crypt to make cookie stealing almost impossible. Only turn off if users cannot stay logged in