Hello ostiii,
The default parameters in the Workflow dialogues contain the last used parameters, so since we are not sure, whether you have ever changed them, please specify all the parameters used in the Build Mesh dialog and the number of points in the dense point cloud. Full processing log that includes the mesh generation process would be also helpful (you can redirect the console pane output to the text file using corresponding option in the Preferences window.
Additionally please check the memory consumption for the current operation.