Do the phrase is possible; it refers to an experiment which did not fulfill its object? That object generally interpreted to be performance of what the experimenter wanted. When an experiment is a failure, it’s a trial of a product and not a

successful strategy.

Both are well spoken people. I don’t see any difference. I’m sorry and I will use the form 2. Sorry… the fact more than two. Unsuccessfully is an adverb which means the same thing as the prepositional phrase without success without a prepositional answer.

After reading there was a question marked “You can’t contact the customer for the price” but can you answer?” To avoid this very slight confusion, you can say I have unsuccessfully tried to contact the customer or I have tried to contact the customer, but have been unsuccessful.

Google shows that “tried unsuccessfully to contact him” has 205 results, “tried unsuccessfully to contact him” has 54 hits, while “tried to contact him, but was unsuccessful” has only 22.