Changes since SOA version
IXFR is a zone transfer request that returns changes since a specific SOA version. Enter the SOA version to request changes since then.
Not an apex domain
The domain 440d9d51fe6f67773eee762b2bfc855c.8326ab9e4d56a99b59e0ff58b940dd3f.a835dc0fde1eb76aa0.sectigo.com is not the root of its zone.
Instead, try zone transfer on sectigo.com .
Instead, try zone transfer on sectigo.com .