To preface, I have very little to no development skills, and unfortunately, the org I inherited as admin is very apex-heavy. I need to make an edit to an apex class (sandbox first of course), but am unable to due to it being part of a scheduled job. We have about a dozen scheduled jobs, all of which are vaguely named. Is there a way I can tell which apex class is running which scheduled job? Of the scheduled jobs, only two of them give me the "manage" option. (see below)

We have a user attempting to make an API call to Salesforce and will intermittently receive this message: INVALID_LOGIN: Invalid username, password, security token; or user locked out..

It doesn't happen every time, but it's happening more and more. I, myself, am not development savvy and am unsure how to assist. 

Login history indicates the following: 

We have already reset the password and security token, and his profile is API Enabled. 

Other than that, I am not sure where to go next...?

To preface, I have very little to no development skills, and unfortunately, the org I inherited as admin is very apex-heavy. I need to make an edit to an apex class (sandbox first of course), but am unable to due to it being part of a scheduled job. We have about a dozen scheduled jobs, all of which are vaguely named. Is there a way I can tell which apex class is running which scheduled job? Of the scheduled jobs, only two of them give me the "manage" option. (see below)

I've verified and linked my Trailhead profile but the badges are not showing up. Any ideas on what I can check?