Here are the upcoming events in the the Webinar in Additive Combinatorics (WAC), hosted by Sean Prendiville, Sarah Peluse, and myself. The main page is here: https://sites.google.com/view/web-add-comb.
Here are some calendars of other online seminars in combinatorics, group theory, or other things in my sphere of research interest. Several subcalendars are imported from other places. One custom calendar is manually curated (a calendar of all events not in their own calendar, a variant of Russell’s paradox).
See also mathseminars.org.
Random Permutations 
Dear Prof. Sean Eberhard,
I am Rusen Li, a phd student in Shandong University, also a visiting research student In UdeM, supervised by Prof. Andrew Granville and Prof. Koukoulopoulos. I am very interested in the Webinar in Additive Combinatorics (WAC), unfortunately, I can’t open the registration webpage, since google.com is blocked in China. Could you please kindly register for me?
Best wishes,
Rusen Li
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Sure, I can do that.
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