This issue has been resolved. Now the problem was that they had a lot of bids on their schedules which haven't been deleted for a while and that was the main reason the schedules didn't show up. To resolve these, anybody with the same issue has to make sure the bids get deleted from time to time in order for the other pilots to be able to view the flights. Another way would be to change the following configuration from "True" to "False" in "core/local.config.php" but I strongly suggest that you go with the first way.
Config::Set('DISABLE_SCHED_ON_BID', true);
Second issue with schedules not showing up properly would be the days of the week and that means if the schedule is not set for today it simply don't show up.
Third issue with schedules not showing up would be that some schedules somehow don't get updated on PIREP submission and the bid column in DB for schedules table, doesn't change from "1" to "0". To resolve this issue you just have to simply change that manually.
Of course there might be some other issues in this regard but these are the most common ones.