Hi,
Without any additional details about your test code and tested application, this might be a timing issue.
For example, if this dropdown is populated with data using some script, it is possible that sometimes script is delayed and this makes it not possible for dropdown to be opened.
Try to add some hardcoded delay before the attempt to open dropdown (say, for 2-5seconds) and check if this solves the problem. If it does, than you will have to figure-out how to determine the moment of time when dropdown can be opened and implement this approach in your test code to make your test more performant and more stable.
No, actually i have implmented all these delays for testing but it stills does not work. However it used to be run fine previously
