Do you get to the in-game menu or not? How is your PC connected e.g. cable or WiFi? Can you connect to other servers OK or is it only this one?
This is initially to discuss and provide help, tips, hints for Csaba Lako who raised his problem in the RF2 Renault RS01 thread https://simracingonline.co.uk/threads/renault-rs01-sport-trophy-series-info.30843/#post-77898
Csaba have you tried the obvious initial steps like using the STEAM files validation for RF2, removed any plugins, removed any newly installed mods that you installed before the problem started happening. Can you connect to a non-SRO server ok? What data rate shows in the RF2 network settings inside the sim?