MacBook does not want to manifest recovery mode

I forgot my Mac password and I want to enable Recovery mode, but when I try the combination of **Command + R** and **Option**, the laptop does not respond, although it has previously responded. The same thing happens with combinations: **Option or Alt**, **D**, **N** and probably **Command + V**, but they work: **Command + S**, **Shift**. In single user mode, when I typed the command `/sbin/mount -uw /`, it said that the operation was not allowed. Does anyone know why? Please reply. Thank you in advance.