$ hugo version
Hugo Static Site Generator v0.76.4/extended darwin/amd64 BuildDate: unknown\
I only had this problem after updating my hugo (which is done automatic) from 0.75 to 0.76.4. Meanwhile, the deployment on netlify by 0.75.1 works as normal. The project can be found here:
Even deleting the callout module does not resolve this issue.
I raised the same issue in the github forum. I suspected this is a bug and I am not familiar with the framework so I do not know how to track it down. Or any suggestion on debugging?
Your website repository is missing the academic theme. My guess is, that it was installed as submodule and you missed to add it to the repo as Hugo module. Check in your go.mod.
Right now you have no layouts directory or theme directory.
Netlify deploy probably works, because you have the submodule cached there. When you delete the cache and deploy manually it might fail too.