Seaquel
SQL Server error code

SQL Server error 2725

SQL Server raises error 2725 at severity 16, which marks a problem with the query or data that you can correct.

An online operation cannot be performed for %S_MSG '%.*ls' because the index contains column '%.*ls' of data type text, ntext, image or FILESTREAM. For a non-clustered index, the column could be an include column of the index. For a clustered index, the column could be any column of the table. If DROP_EXISTING is used, the column could be part of a new or old index. The operation must be performed offline.
Msg2725
Severity16
Group2000–2999

Source: Database Engine events and errors