Describe the sequence
Say whether water appears with a full sink, while emptying or during operation. Keep the top mounting and outlet observations separate.
Choose work after inspection
An external connection and a damaged casing lead to different proposals. Do not cover the unit in sealant or assume a universal reseal can resolve the problem.
A useful distinction
A joint may appear dry until the sink is emptied, while another leak can occur with standing water alone. That ordinary timing distinction helps assessment without asking you to fill a leaking installation repeatedly.