Set Video Profile in Ffmpeg

ffmpeg -i v.webm \  -c:a libopus -b:a 128k -ac 2 -ar 48000\
    -c:v libvpx-vp9 -pix_fmt yuv420p -profile:v main -b:v 2M t.webm

Registered the parameter

-profile:v main

When executed it gives an error

[libvpx-vp9 @ 0x560e172daac0] [Eval @ 0x7f2d77ffd240] Undefined constant or missing '(' in 'main'
[libvpx-vp9 @ 0x560e172daac0] Unable to parse option value "main"
[libvpx-vp9 @ 0x560e172daac0] Error setting option profile to value main.
[vost#0:0/libvpx-vp9 @ 0x560e172a5700] Error while opening encoder - maybe incorrect parameters such as bit_rate, rate, width or height.
[vf#0:0 @ 0x560e172dc280] Error sending frames to consumers: Invalid argument
[vf#0:0 @ 0x560e172dc280] Task finished with error code: -22 (Invalid argument)
[vf#0:0 @ 0x560e172dc280] Terminating thread with return code -22 (Invalid argument)
[vost#0:0/libvpx-vp9 @ 0x560e172a5700] Could not open encoder before EOF
[vost#0:0/libvpx-vp9 @ 0x560e172a5700] Task finished with error code: -22 (Invalid argument)
[vost#0:0/libvpx-vp9 @ 0x560e172a5700] Terminating thread with return code -22 (Invalid argument)
[out#0/webm @ 0x560e17294680] Nothing was written into output file, because at least one of its streams received no packets.

How to correctly specify a profile for a video or with the libvpx-vp9 codec, is it not relevant? I don’t understand…