What’s taking so long to get a start date?

I got an offer two weeks but I still don’t know start date yet. I followed up with my recruiter and she said the person who decides was out on vacation last week but I should know this week. It’s Wednesday know but it’s been crickets. I’m a little nervous because some of my previous coworkers who didn’t really like me are apart of the team and started thinking the worst like “did they say something bad about me?” But wouldn’t they let me know asap if they’re withdrawing the offer? So idk anymore 😭 usually jobs have started fast after I got done with background and reference checks.