Great to hear that you resolved the curl issue.
This is not an error, it’s just a notice, informing you that upon plugin activation your admin user was given the manage_wallets capability:
https://github.com/dashed-slug/wallets/blob/6.2.5/admin/capabilities.php#L310
You should be good to go. Please let me know in a new thread if you have any more questions about the plugin.
with regards