I think there is some plugin conflict due to which you are facing this issue.
Have you tried zeroing on which plugin conflicts with the theme?
First, we need to confirm it is a plugin conflict –
The best way to do that is to disable all plugins and try to check for the issue – does it work?
Yes – means it is a plugin conflict.
So the next step is to zero in on which plugin is impacting the theme –
Please enable each plugin one by one and check the issue – so you can find out which plugin causes it to break.
If there doesn’t exist a plugin conflict, can you just check your Permalink setting?
You can find the option in Setting–>Reading. If the “post name” is not selected in common settings, change the setting to post name and check for the issue.
Try above solutions and do let me know if you are still facing the issue.