As posted by bluediamond, its a known issue and will be solved. From the information that we have, this issue pertains to the Default Style only and all other styles are working fine. If you wish, you can switch to some other style for the time being.
@iosoft
There's no way we are going to increase the existing storage limits for PMs. Incase you're finding it hard to adjust, I suggest you download all your old PMs and free up your inbox.