Stena Line would like to advise that due to technical problems our 22:00hrs sailing on Monday 31 July from Belfast – Birkenhead (Liverpool) has been cancelled. Please call 03432 081 801 to amend your booking. We would like to apologise for any inconvenience caused.
https://www.stenaline.co.uk/ferries-to-britain/latest-sailing-updates/belfast-liverpool
NI Ferry Site understand the cancellation is due to a technical issue with STENA MERSEY.
Update: Sailings resumed the following day