Super quick summary using quotes from the article:

This [theory] can be tested by timing radio pulses between Earth and Cassini. Since Cassini was orbiting Saturn, this helped to measure the Earth-Saturn distance and allowed us to precisely track Saturn’s orbit. But Cassini did not find any anomaly of the kind expected in Mond.

Another test is provided by wide binary stars – two stars that orbit a shared centre several thousand AU apart. Mond predicted that such stars should orbit around each other 20% faster than expected with Newton’s laws. But one of us, Indranil Banik, recently led a very detailed study that rules out this prediction.

Ultimately though, Mond, as presently formulated, cannot be considered a viable alternative to dark matter any more. We may not like it, but the dark side still holds sway.

They had to accept the null hypothesis. Not a bad thing, the point of science is to determine what's true, not reinforce what you want to be true.

Still doesn't explain dark matter though. We have a number of experiments searching for it, and they've yet to even get a hint of confirmation of its existence. Whatever the resolution to this is, it's probably not dark matter either.