Efforts have been going on for centuries to provide conclusive evidence for the claims of astrology but have not met with any success; therefore we must conclude that astrology is nothing but nonsense. Which informal fallacy is committed in the above argument?

The argument treats the mere failure to prove astrology as proof that astrology is nonsense.

Centuries of effort have produced no conclusive evidence for astrology's claims.

From this lack of established proof it concludes astrology is worthless.

But not-yet-proven is not the same as disproven or false.

Concluding falsity from an absence of proof is the appeal to ignorance.