Alumni can only access certain specific electronic resources from off campus for personal, non-commercial use. Please refer to the list of resources available to alumni, on the Alumni electronic resources webpage
The key thing is step #1 which is making your alumni watcard active.
I had the same problem and turns out even though I received my alumni watcard by mail it was not registered on the library website.
After completing the alumni request form and the watcard arriving by mail, you have to complete the "register your alumni watcard" form which was confusing at first because it looks almost identical to the request form so I thought I already filled it but i haven't.
This must be filled out after the alumni card arrives by mail then you must wait for them to register your account which shouldn't take too long:
https://uwaterloo.ca/library/alumni-and-community-members/how-access-resources/register-your-alumni-watcard/done?sid=4024&token=cd8ae570c5d810d390354fcd05883ce6
I had the same problem and turns out even though I received my alumni watcard by mail it was not registered on the library website.
After completing the alumni request form and the watcard arriving by mail, you have to complete the "register your alumni watcard" form which was confusing at first because it looks almost identical to the request form so I thought I already filled it but i haven't.
This must be filled out after the alumni card arrives by mail then you must wait for them to register your account which shouldn't take too long:
https://uwaterloo.ca/library/alumni-and-community-members/how-access-resources/register-your-alumni-watcard/done?sid=4024&token=cd8ae570c5d810d390354fcd05883ce6