Seeing minimal bash-like line editing is supported when booting to grub for lubuntu 20.4

I have successfully installed lubuntu 20.4 on unallocated space and grub is installed, I just have to change to ubuntu in boot options. unfortunately, grub says Seeing minimal bash-like line editing is supported. I don't know what to do because it is completely unusable and I cant get to lubuntu but I know it is installed. Any help would be appreciated.