I'm running a server with Windows 2008 r2 OS. The server is used as a Web server. I'm logging to the server remotely using rdp. I've noticed that when I have Internet connection problems, and I'm logged in to the server, it causes serious lags to the website. (of course that I checked with another users and they're having lags too). Is it rational that my connection causes problems on the server through the rdp? Thank you.
This could be if your server's connection to the internet is very slow and limited. It could also be whatever you are running during that RDP session which could, possibly though uncertain due to lack of data provided, take server resources and leave the web server with not enough resources, or you are causing your server to swap.
Basically, there are a lot of options. A web server is normally best left without users logged onto them (or any servers for that matter) as GUI generally use up a lot of useful resources and users (even admin) can easily "take down" a server by using it as a workstation (like opening a 5GB log file in Notepad).
All in all, there is not enough data to give a conclusive "answer" but above are general points that apply to your question.