Ctrl+L stopped clearing screen in PuTTY sessions [duplicate]
Solution 1:
As suggested in the comments I found out that another program had taken over keyboard shorcut for clearing the terminal screen.
I used methods descriped in How do I find out which programs have registered global hotkeys in Windows 10? to find program that had taken over the key combination.
After I changed keyboard shortcut in the other program clearing terminal screen in Putty started working again with Ctrl+L.