Just tried to add a recent publication. The first author has already put it up on Research gate (RG). When I tried to add the publication (of which I am senior author) RG automatically blocked after uploading DOI - and told me to use the existing copy. But there is no instruction how to do so and no obvious way to claim authorship if I access the first author's page. In the past, RGhas always recognised my name and emailed to asked me to claim authorship. For some reason it has not done that this time. And there is no help function I can find..

Does anyone know what to do?