I have just published v 2.6.0. Added support for https:// sites.
Update to the new version, choose pro version if not already done. Then go to settings > assets and enable “Host Coin Hive Script”. Finally click “Update coinhive Scripts”.
It seems that you have been blacklisted by avast when using coinhive unencrypted some time. Maybe you can ask in avast forums how to remove the ban.
The current version of the plugin encrypts the coinhive scripts and is not detected by avast as you can see by navigating to https://www.wp-monero-miner.com.