We at GTAccess Denied (Crew) found a solution for most Connectivity & Character lose problems.
The problem is not directly R* fault, but your "Local Internet Provider DNS" with stands for (Domain Name Server)
Most provider have crappy DNS, with big routeing firewalls that seem to block the domains that rockstar is using for their cloud servers!!
To fix this your can use googles open DNS servers, in your XBOX or PS3.
1. Go for the XBOX to Setting > Network settings > Box 2 with dns server setting and choose "Manual"
Add 188.8.131.52 as primary and 184.108.40.206 as secondary, then done.
2. Clear your xbox system cache!!
3. Turn off your XBOX for a minute, then your ready to play!!
For the PS3 its must be somewhere in network settings, look for is.
Also you will still get from time to time a cloud server error, but the retry button will not abort your connexion by default, en you get back in 2-3 tries!!
Also this will not fix items and cars and more, that are not saved even if you exits out though start > Online > Leave GTA Online. I should know I lost 4 tacked & insured cars even with this fix.
And Rockstar, put something up abort DNS Connectivity issue this ^^ is a good temporarily fix!!
Im posting it here, because rockstar is blocking ip in comments and maybe someone can make PS3 guide to change DNS Server?