I have submitted my paper on 12-Jan-2019. The journal uses ScholarOne Manuscripts for online submission. The status has been changed to Awaiting Reviewer Scores in the same week I created the submission.
I've recently contacted the editor about the status of the manuscript on 8-Apr-2019 and he replied that he is waiting for an overdue review, the the reviewer wa chased on 5-Apr-2019.
At this point, I know I should wait. But it's interesting to know if I can send another reminder and when should I do that. Especially when the editor actually reported what is going on and didn't simply mention that the paper is "Under Review" and I should leave it like that until a decision is made.