Hi xfechx,
That’s unfortunate but we have seen a few cases of this recently and it has invariably been due to conflicts with other plugins or even certain themes. To bear this theory out, can I ask you to:
- Ensure The Events Calendar/Events Calendar PRO are up to date
- Deactivate all other plugins
- Switch to a default, unmodified theme such as Twenty Twelve
- At this point, visit the Settings → Permalinks screen (you need change nothing, visiting this screen is sufficient to “clear out” a number of stored rules and freshen things up)
Now test and see if you can access the single events. If you can, start reactivating everything else one-at-a-time and test at each stage to see if the problem has returned – this could help to isolate the source of the problem.
Thanks – let us know how you get on 🙂