I apologize, you may be affected by a service disruption if this is only affecting one area. We have identified a service provider problem, and will update our status page with more info soon: http://status.gotomeeting.com/
Hi Gabriela, I'm sorry to hear you're experiencing this issue with joining your meeting. Are you and your affected colleagues all on the same network? If so, do you have a cellphone capable of using cell data to create a WiFi hotspot to temporarily connect to? It's possible that our traffic is being blocked or hindered in some way, and your IT department may need to review our firewall configuration guide.
Each environment is going to be different, but the firewall document referenced above contains static information concerning the GoTo connections, IP ranges, and executable files to be allowed. Depending if you are in a home environment or office, and if you have local software firewalls or networked, the steps could vary greatly.
Have you checked out the document and started troubleshooting the network or firewalls?