Sewer odours inside can suggest a dry catch, fractured vent

https://learn.multnomah.edu/eportfolios/918/home/why-you-need-a-plumber-to-clear-blocked-drains

Sewage system odours inside can indicate a dry catch, fractured vent, or partial obstruction; Geelong homes with large trees or older sewer lines might require CCTV examinations to locate invasions and stop recurring smells.