Last year we had a few hundred students that did not get Canvas accounts generated from SIS imports. Our previous Canvas admin was creating these manually. I have found the problem. The students needed email addresses entered into PowerTeacher Gradebook (PTG). Apparently there is difference between having an email address in PowerSchool (PS) and PTG, but I can't see under the hood in PS. Those students who were manually created will be blocked from syncing with the SIS.
To fix this, I go in and modify their SIS ID, sign on, and email in Canvas. Example student_1234, first name.lastname, email@example.com would be modified to be student_1234a, first name.lastname01, and firstname.lastname@example.org.
This will allow the SIS to create the real account for the student, but it happens at random. On 9/5/2017 I had a massive error log where it tried to import data. I found that many of these were still the old manually created accounts, so I spent hours changing these to the temp info described above. Last night SIS import did not try again for any of that data. Sometimes it tries again and fixes the issue, but I can't figure out when exactly it does this. I changed many of those last night, but now they will not be able to log on today unless I change them back. How do I make the SIS try to create the users again?