Hi,
He may have swallowed substrate or could have an intestinal obstruction?
What kind of substrate(s) do you have in the enclosure?
Have you found any poop in the past day or 2?
What are you feeding the frog?
What size is the feeder ?

If you suspect this could be possible, get him into a de-chlorinated water to soak --- try to get him to stay there for quite some time, even if you have to cover the soaking dish to keep him in the water. 30 minutes ( temped water --not cold / not hot...comfortable on when dribbled on your wrist)

Provide a - clean- shallow soaking dish (water should not be above his chin)
Not tap water !
If you do not have amphibian safe water de-chlorinator-get it as soon as you can.
In the meantime use bottled 100% spring water from the market.

Do not feed him until he poops.

Please ..........Keep us posted.