Creating subdomains for landing pages but getting SSL errors

Hi i am trying to set up a subdomain lp1.pipelinedigital.com.au but I’m running into SSL chain errors (I think??) and I am appealing to the webflow brains trust!

  1. I have a built a landing page site landing1.com.au (SSL certs looks fine)
  2. my main site is pipelinedigital.com.au (SSL cert chain error - see below)
  3. landing page site for google ads is lp1.pipelinedigital.com.au (SSL cert chain error - see below)

I suspect its a SSL issue however both of these sites are Webflow sites.

I used this tool to example and got the following errors:
SSL Checker

The SSL cert for both landing1.com.au and lp1.pipelinedigital.com.au is complaining as below:

None of the common names in the certificate match the name that was entered (lp1.pipelinedigital.com.au). You may receive an error when accessing this site in a web browser.

:closed_lock_with_key:SERVER
Common name: webflow.io
SANs: webflow.io
Valid from: February 25, 2023 to March 28, 2024
Serial Number: 01ef8887b36128c7963f8350d30d0a2d
Signature Algorithm: sha256WithRSAEncryption
Issuer: GlobalSign Atlas R3 DV TLS CA 2023 Q1

:closed_lock_with_key: CHAIN
Common name: GlobalSign Atlas R3 DV TLS CA 2023 Q1
Organization: GlobalSign nv-sa
Location: BE
Valid from October 11, 2022 to October 11, 2024
Serial Number: 7d4d424a0bd1ed1a3512a8e24955356c
Signature Algorithm: sha256WithRSAEncryption
Issuer: GlobalSign