Ahh I see, are you using custom auth to get the JWT? I just want to double-check since OAuth 2.0 came up in this thread.
For custom auth, I'd be curious to know if you've already set up a custom auth refresh flow. If the Zoho API responds with an error code when the JWT expires Retool will detect that and automatically run the refresh flow you have set up, so you can use that to refresh the token.
If you're using OAuth 2.0 then the refresh flow should be handled more automatically so I'd be curious to see screenshots of your setup for instance, along with screenshots of any errors you might be running into when they expire to see what might be going wrong there 