The reason for the short notice cancellation was that several COVID cases had been identified onboard the ship affecting major service operations.
TUI Cruises said in a statement they were "confirming the short-term cancellation of the Caribbean cruise for newly arriving guests, booked on Mein Schiff 2."
The ongoing operations with passengers remained unaffected: the cruise that started on January 14 (from La Romana Dominicana) continued as planned. For another group of passengers, their voyage came to an end in Bridgetown.
TUI added the reason for the cancellation was individual cases of COVID that had been identified during routine tests. In accordance with the process of the company's health protocols, the affected individuals had been immediately isolated in a specially prepared area. All positive cases had only mild symptoms.
"Among the people who tested positive are some positions that are important for the service area. Therefore unfortunately TUI Cruises cannot offer the usual service that the guests of the Mein Schiff fleet expect and are used to. The usual Mein Schiff service can therefore not be guaranteed with more guests on board. In addition, the authorities in Barbados cannot guarantee us to release for new guests at the moment."
Currently, there are ~1800 passengers plus ~800 crew on the liner.
For more Mein Schiff 2 incidents and accidents see the ship's CruiseMinus page.