Rockstar posted a list of known GTA Online bugs, which you can view on the developer's support site below. Keep in mind, Rockstar is working on these.
Here's where things stand, at the time of writing:
- Occasional "Rockstar Cloud Servers Unavailable" error message
- Freezing sometimes while loading into first race in GTAO with "waiting for other players" on the screen
- Intermittent "Failed to Host a GTA Online Session" error messages
- Race Corona (start area, marker) occasionally not showing up for first race
- Errors saying "Timed out when matchmaking for a compatible GTA Online Session to join"
- Occasional errors about jobs failing to start or load
- General issues with the Social Club site and Social Club features (slow loading, failed logins, emails not arriving, etc). For more information on Social Club status, please see: http://support.rockstargames.com/hc/en-us/articles/200357093
- Misc. network and server-related error messages, disconnections, or cloud server errors
- Errors saying "Mission Failed" as soon as the mission begins during a session
GTA Online Launch Status — Latest Updates [Rockstar]