When you log in and you select “forever” for remembering your account, your phone/tablet/computer should save a small piece of data to remember that you are always logged in. However, some devices have a higher level of security set on them and will not allow saving of this type of information. Unfortunately this is something you would need to change on your side.

The higher security is usually set for online banking etc. but it can affect simple websites like the message board also.