[EDIT: edited this comment substantially.]
Speaking as an analytic number theorist, the branch of math of which the Lindelof Hypothesis is part, could you tell us what you personally think of the paper?
(Let's try to avoid just gratuitous negativity:
https://blog.ycombinator.com/new-hacker-news-guideline/ )
I read the paper after you linked it and it seems serious. Fokas is the guy who invented the Fokas Method - https://en.wikipedia.org/wiki/Fokas_method
Structurally this is what my impression is of the paper (I don't understand the math):
The result seemed very well-presented, includes background and a 2-page inroduction, summarizes the derivation of the main result from page 5-12, derives its main theorems and lemmas used, and then from p. 50-52 summarizes it all again. Finally three appendices in 4 pages provide some numerical verification (a sanity check) and an acknowledgment section says "This project would not have been completed without the crucial contribution of Kostis Kalimeris. Kostis has studied extensively the classical techniques for the estimation of single and multiple exponential sums; these techniques are used extensively in our joint paper with Kostis [KF] and some of the results of this paper are used in section 6. Furthermore, Kostis has checked the entire manuscript and has made important contributions to the completion of some of the results presented here." There are another 7 paragraphs of acknowledgments going back more than 3 years, and finally 3 pages of references, including to private correspondence and preprints.
The affiliations on the paper are Department of Applied Mathematics and Theoretical Physics, University of Cambridge, and Viterbi School of Engineering, University of Southern California.
Additionally, this researcher has a proven track record, his Wikipedia article says:
>He has made seminal contributions in a remarkably broad range of areas which include: symmetries, integrable nonlinear PDEs, Painleve' equations and random matrices, models for leukemia and protein folding, electro-magneto-enchephalography, nuclear imaging, and relativistic gravity. Also, he has introduced a completely new method for solving boundary value problems known as the Fokas method, which has been acclaimed as the most important development in the analytical treatment of PDEs since the introduction of the Fourier transform
He is the winner of the Naylor prize (past winners include Roger Penrose, 1991 and Stephen Hawking, 1999, among others) and holds 7 honorary doctorates (right side of his Wikipedia page.)