invite fail

Invited my students into my HUM 101 class today and for the most part, it went great. But there have been two instances now where the invite link opens to a blank white page. In one case, I was able to send a second invite and the link worked that time. In the other, the student actually moved to a different computer and use the link from another student's email account and was able to sign up successfully that way. But I don't know what was causing the problem itself.
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