Use the message on screen. Each one points at a different purchase.
Too cold
You are above the current warmth limit. Go home, sell, and buy Climb Higher if this happens before the bag is full. Pushing the same ledge again without warmth repeats the health loss.
Backpack Full
You cannot pick up more. Sell at the Gem Buyer, or stop looting low grades. Carry More is the upgrade when this happens while you are still safe. A Crystal Filter is reported in settings if Common, Uncommon, and Rare drops are the clutter.
Too heavy for your bag
The crystal exists, but its kilograms exceed capacity. One session could not lift a 54 kg crystal after a small bag upgrade. Buy Carry More, or leave that crystal and take lighter ones that still pay. Do not confuse this with a pickaxe problem.
Pickaxe will not break it
A pickaxe-level warning, or a health bar that barely moves, means Power is short. Buy the next shop pickaxe. The reported Mossite Boulder, at 308.8K HP, is said to need the Titanium Breaker. Other formations can have their own gate. Read the warning on that rock.
The sell did nothing
Be at the selling point with crystals still in the bag. An empty bag and a garden full of crystals will not pay Cash. Garden placement is luck, not a sale.
A code did nothing
No working code is confirmed, and the redemption control is not confirmed. Codes from other mining games fail here because they are not for this experience. See the codes page before you try another string.
Someone else picked up the node
Servers hold 8 players. A crystal on the ground can be taken. If a node matters, break it and pick up what you can carry before you walk off to shop.