1. Insufficient baking time: If the baking time is insufficient, the inside of the cake may not be sufficiently heated, resulting in the inside of the cake being wet.

2. Inadequate protein distribution: Inadequate protein distribution is one of the key problems in making cloud cakes. If the protein is not sufficiently distributed, the protein cream can't support the organization of the cake and make the inside of the cake moist.

3. The cake paste is not evenly mixed: If the cake paste is not evenly mixed, it may lead to uneven density inside the cake, and more baking time is needed in places with more wet materials, which may easily cause some places to be mature, but some places are not yet mature and still wet.

4. Incorrect mixing technique: If the mixing technique is incorrect, it will easily lead to serious defoaming of batter. The batter is defoamed, causing it to be in a relatively thin state as a whole, which makes it wetter and less likely to be cooked.

Generally speaking, in order to avoid the cloud cake from being wet, it is necessary to ensure that the baking time is enough, the protein is fully distributed, the cake paste is evenly mixed and the correct mixing method is adopted.