When your Fish, Wood or Iron storage is full on Berk, the excess resources will be sent to your mailbox.
You will then receive a mail where the resources will gather. The mailbox will automatically create a new mail when the resource limit of each mail is reached.
Resources from the following goes to your mailbox;
- Card Packs
- Gauntlet Wheel
- Seasonal Statues
- Quest Rewards
- Calendar Rewards
- Johann's Secret Speed Sales
- Mailbox