This is a technical term specially used in Hindu logic. When the cause and effect series becomes infinite and does not serve as a proof, it is called anavasthā (infinite regress) and hence rejected.
This anavasthā is sometimes divided into two varieties: prāmāṇikī or valid, and aprāmāṇikī or invalid. For instance, in the series of bīja (seed) and vṛkṣa (tree) the infinite regress is valid and natural. Hence it is prāmāṇikī. On the other hand, while trying to prove the existence of a cause for this world, if that cause (called Brahman) is accepted to have been caused by something else, it leads to anavasthā, infinite regress, and hence to no definite conclusion. This anavasthā is aprāmāṇikī or invalid. (To avoid this, Vedānta accepts Brahman as the uncaused cause.)