The phrase "again unsuccessfully" is correct and usable in written English.
It can be used to indicate that an attempt was made once more, but it did not succeed.
Example: "After trying to fix the issue again unsuccessfully, we decided to seek professional help."
Alternatives: "once more without success" or "yet again to no avail".
And in 1988, he mounted another challenge to the leadership - again unsuccessfully.
But that was overturned on appeal, forcing the family to turn, once again unsuccessfully, to the civil courts.
He was defeated in the 1955 general election and four years later stood in Ilford South, again unsuccessfully.
He lost that year, but caught the electioneering bug; he ran again, unsuccessfully, in 1990 and 1993, garnering more votes with each try.
Who did they think they were protecting in their distorted, programmed little minds as they tried and tried again, unsuccessfully, to slither up the slippery pole of western society?
In 1922 and 1923 Russell ran twice more for Parliament, again unsuccessfully, and together with his second wife, Dora, he founded an experimental school that they operated during the late 1920s and early 1930s (Russell 1926 and Park 1963).
In 1773 they again speculated unsuccessfully in a group of stuccoed terraces in Portland Place, London.
In 1938 Blum again tried, unsuccessfully, to establish a popular front ministry.
By 130 the city had been partially repopulated, and the Jews again revolted unsuccessfully against Rome from 132 to 135.
Charles the Bad once again revolted unsuccessfully, his dynastic claim to Burgundy running afoul of the king's; the succession to Brittany was settled by arms in favour of the Anglophile Jean de Montfort (who became John IV [the Valiant]).
Later that year she again stood unsuccessfully for the House of Commons, this time in the Ontario riding of London North Centre, though she surprised pundits by winning 26 percent of the vote.
