Why do you get Internal Server Error in WordPress?
First of all, Internal Server Error is not specific to WordPress alone only, it could happen to any CMS or websites. What is more frustrating is that it really doesn’t tell you what you did that causes this to happen.
The frequent causes
1) You have just installed a new theme (so be sure to check the theme properly before activating, or you could check with your theme provider for more information on this matter). It could be a theme functions.
2) Plugins. This cause is highly likely as all plugins are almost completely different in functions. (you can try to deactivate the plugin(s) that you have installed. And check your website again on another tab to see if it still returns the error.
3) Check for corrupt .htaccess file. Renaming your main .htaccess file to something like .htaccess_old. To do this you can either login using your FTP or login to your cPanel. Once you have renamed the .htaccess file, open a new tab and try loading your site to see if this solved the problem. If not, go to your WordPress dashboard, go to Settings » Permalinks and click the save button. This will generate a new .htaccess file.
4) Deactivative all plugins. Then try loading your website on another tab to see if this works. If it does, then you can slowly repeat the steps by activating one plugin at a time and loading your website to see which plugin actually clashes with one another. Unfortunately, this is a long process but this often works.
5) Email us, and we’ll upload the latest working WordPress backup to your WordPress site. and we’ll make sure that your website is up and running again.