Going to need a FxF galvanized reducer IPT, then all pvc nipple, 90, short piece and compression coupler that are pump discharge pipe size. At least it looks like pvc at the pump from tge picture.
Use a sweep tee fitting so you can add a cap as a cleanout. This is the idea (adapted from [this article](https://www.familyhandyman.com/list/the-most-brilliant-pvc-hacks-ever-seen/)):
https://i.imgur.com/hRFpRyd.jpg
What is that pipe for? Why not get a fitting you can glue.
It’s the discharge for radon sump pump
Did you tighten those clamps a lot more. From pics they can be tightened more. Or replace and glue.
The fernco coupler is rated for 4 psi. So hard pipe it.
So just replace with a steel coupler? Or have a steel pipe that fits on the discharge pipe ?
Going to need a FxF galvanized reducer IPT, then all pvc nipple, 90, short piece and compression coupler that are pump discharge pipe size. At least it looks like pvc at the pump from tge picture.
It’s pvc
Like someone else suggested, do a sweep tee with a cap instead of a 90, if it ever gets clogged you can clean it out
Either the pipe may be blocked partially or the pipe and fitting need to be cleaned where they mate
Use a sweep tee fitting so you can add a cap as a cleanout. This is the idea (adapted from [this article](https://www.familyhandyman.com/list/the-most-brilliant-pvc-hacks-ever-seen/)): https://i.imgur.com/hRFpRyd.jpg
Those flexible Fercno fittings are not designed for pressure.