I have heard 2 pronunciations of "Often" though only one is found in most of the dictionaries.
1) Often: Ofn (normal pronunciation)
2) Often: OfTen (a prominent T sound)
The no 2 pronunciation is British or American?
Which one popular and widely accepted?
When we were learning English 20 years ago in China, we were told to pronounce 'OFN'.
After years, however, I found more and more people say 'OFTN'.
Finally I asked an English linguistic professional, and she said both are correct, whereas 'OFTN' is more widely used in North America.
The T in often would be silent.
The T in often would be silent in the speech of someone who believed that there was only one correct answer, and that that answer was that the T should be silent.
As previous answers have said, both pronunciations are acceptable. There was a silly prescriptive rule in favour of many 'silent' letters; the suppression of the T in 'often' is one of the more tenacious shibboleths (it was drummed into me for my first 5 years, and going to school was an eye-opener - 'What were these people saying?'). But very few people today omit the L in 'golf' (which used to be regarded as the only acceptable pronunciation).
I hear both, but usually we pronounce it without the T sound.