I recently became the line manager for a team of engineers, which includes a two-people subteam based in a different location (very far away from here, I haven't had a chance to visit yet, but it's something I'm planning to do).
The two people in this subteam, Alice and Bob, don't really get along well, in particular, Alice doesn't like Bob.
The relationship that makes up this situation is summarized by:
Alice is senior to Bob in terms of years at the company, but not age
Alice and Bob can't really communicate and pretty much ignore each other
Alice openly expresses her dislike for Bob (to me, the rest of the team, and sometimes customers)
Alice said she tried to fix this situation with Bob (not sure how) but it's now too late and she can't do anything about it
How can I, as their (remote) line manager, try to fix this mess?