Here is all right way:
1# run command line:
Nano /etc/letsencrypt/config/account.conf
2# add the following line:
DEFAULT_CA=https://acme-v02.api.letsencrypt.org/directory
3# Save & close.
4# After "Save & Close" of Nano editor, you have to exit the terminal and reopen a new terminal, and run the command line:
acme.sh --set-default-ca --server letsencrypt
It will show as below:
Fri Aug 27 04:01:52 UTC 2021] Changed default CA to: https://acme-v02.api.letsencrypt.org/directory
5# and now you should able to create site as usual like this way:
export DO_API_KEY="6255df99cbcaasd0606s52694cfdddddc225f8b87a286e5dfec8e7fa367e07866dgd4c7g91212"
sudo -E wo site create mysite.com --wpsubdomain --wpredis --php74 --letsencrypt=wildcard --dns=dns_dgon