Hi Diegz,
I hope you are well today.
There might have conflict betweek the 2 plugins, as some feature are similar and hook into core like the Login protection. So I suggest to turn it off by visiting WP Defender->IP Lockout, and disable the Login Protection.
Other features can work together I think. But for safe you should have a full backup before process.
If you have any additional issues, please let us know and we’ll be happy to help.
Best regards,
Hoang
@diegz thank you for your interest! As Hoang mentioned, we have not had any issues or complaints reported but this would be like any other plugin – where there are overlapping features, you would only activate the feature in one of the plugins. If you do encounter any issues with defender and Jetpack please let us know. We are always working on improving Defender and want to address any conflicts.