Try not to use problems alerts, if u don't know Ranking Criteria:
Rules for hard:
Rules
Objects 1/2 of a beat apart or less must not fully overlap. Slider heads or tails fully overlapped by slider tails are exempt, so long as their sliderbodies are visible.
Do not use slider reverse arrows that do not follow the visible slider path. These misrepresent the direction of a slider.
Every slider must have a clear and visible path of movement to follow from start to end. Sliders that overlap themselves without straightforward slider borders and sliders whose individual sections are unreadable cannot be used. A slider's end position must be clear under the assumption that a player has a skin which makes slider end circles fully transparent.
Ambiguous sliders with follow circles that cover the whole slider path are allowed, assuming the slider borders are straightforward.