EDIT (problem solved)
1/Opened their website
2/copied the URL they provide me
https://grin.gateio.live/deposit/gateiogrin/0017b6f782083004
3/add the port :3415 to the link to be “https://grin.gateio.live/deposit/gateiogrin/0017b6f782083004:3415”
4/sent the money
5/nothing in my account
6/contacted support, waiting …