Someone did a review of his previous work on Riemann hypothesis [1]. Not into this field, but apparently that blog is being run by someone credible [2]. I have found a link to [1] via this forum [3].

[1] https://web.archive.org/web/20220128195023/https://motls.blo...

[2] https://en.wikipedia.org/wiki/Lubo%C5%A1_Motl

[3] https://www.scienceforums.net/topic/124368-has-the-riemann-h...