Hi widfara,
as I said, this theme has been downloaded more than 50000 times and actually no other user has this problem and I can’t also not reproduce this, so this definitely has to be something related to your site or WordPress installation.
If you have tried all solutions provided by Esmi and those solutions you can find on the net, I can’t help you either, because then I have no idea what’s going on on your site. But as you can read in all those articles regarding this topic, the problem might not be solved just by deactivating plugins. There is more you can do and you should try these things….
And as you know, you are using this theme longer than three days and you know also that it was working fine before. So actually, you must have installed or modified something which has caused this.
By the way, don’t forget that you are using a FREE theme, you did not spent a single cent for it and you actually are getting free support here! But your issue is beyond theme support and is not caused by the theme, otherwise more people would have this issue and I also could reproduce it. So actually it has to be something which is happening on your site and that’s your responsibility, as a webmaster.
The only thing I can offer you is that you send us your admin login and I will have a look, but that actually is already more than what you can expect me to do…: https://www.mhthemes.com/contact/
And you are always free to change the theme, if it solves your issue and is your preferred solution, go ahead. ??
Regards
Michael
EDIT: What you also can try is setting up a new WordPress installation and database as a test and then try again. If it works, you will definitely know that’s not the theme.