Not put into champion select after accepting queue

This is like the fifth time this has happened to me. Decided to report this now because first time happened during a ranked queue and lost 10 lp. The bug I have is when I accept queue, I'm not put into champion select. I hear all the sound effects from champion select, but I'm not in it. Eventually, it ends up dodging because I couldn't pick a champion. I tried making a custom game while it was happening, the popup that showed up is in one of the screenshots below. My computer is like 7 years old and things do tend to run kinda slow occasionally, especially the client that takes as much ram as the game itself. Is my toaster the problem? I don't know, please help. Thank you.