There are a several issues here:
- you are using outdated components see GVM-10 (old stable, initial release 2019-04-05)
- you should use a newer version of gvm-tools Stable releases for gvm-tools and python-gvm
- GVM 10 doesn’t use the TLS connection. You have to use the socket connection instead
- GMP is a XML protocol. XML needs closing tags. You have to use
<delete_task task_id="..."/>