Why am I getting this error?

Hmm… Sometimes, the data won’t save, even though I changed them. Is there a fix to it?

Im not sure, if i were you try re write the datastore but simpler, not using tables just normal values. If your just starting out with datastores i would just do that and then in the future try use tables

So, you are suggesting to have multiple datastores instead of one?

Use the same datastore, but just a different key.