Sometimes this can be an indication that something about your open challenge seems strange to your opponents.
If your live chess rating is around 1250 and you set your challenge to be max 1050 for your opponent, this will mean quite a big difference of at least 200 points in your favour. Some will be okay with that, but some may prefer more equal opponents, so they may not like the matchup they got and maybe even abort the game.
Or maybe it is also an indication that your opponent is not yet used to recognizing your rating from the challenge info he is seeing. As soon as he has gotten used to recognizing that some way, he may easily stop accepting your open challenges if he does not wish to play them.
A few times now I've created a new game in live chess. I put in my criteria (10 minutes, rated, max 1050 opponent for example) and as soon as I click to create the game someone accepts the challenge. They then abort. I create the game again and immediately the same person accepts, and aborts. I'll do this again and again. Is this person somehow automatically accepting the game or are they just being a jerk? How can I avoid this when I want to issue an open challenge?