I don't know what causes your issue. try to copy the app and re-create it again, then delete the app that have errors.

Undeployed the  app and return it to the prototype state. 

if its only you, you can disable the user sign in requirements here just untick the require user sign in.

May I ask a question?You just want to log the time and the oxygen measurements right? If that is the case you can use it like this.Please don't mind the name of the tables and columns. I just created that action while doing some projects. I don't hav...

I did mine through Google App Script. But take note of the Quotas https://developers.google.com/apps-script/guides/services/quotas