Internal Server Error

I am facing issue while installing Paid Wordpress theme of compressed size 12 MB into the wordpress App on my Parallel Plesk Panel .Even I have tried using FTP for the same but no solution.Please guide.The error log goes as Internal Server Error

 

In order to investigate this issue please contact Plesk Support using this link.
Thank a lot for understanding.

 

I am also facing this issue while installing a paid WordPress theme. I even tried using FTP, but it didn't work. I was trying Loco Addon on my Parallel Plesk Panel. Getting an 'Internal Server Error' and not sure how to fix it. Did you find any solution?

 

It sounds like your server is blocking the upload due to PHP limits or a misconfiguration in Plesk, not because of the theme itself.

Here are the main things you should check:

✅ 1. Increase PHP Upload Limits in Plesk
Go to:
Plesk → Domains → PHP Settings

Increase these values:

• upload_max_filesize → 64M or 128M
  
  
• post_max_size → 64M or 128M
  
  
• memory_limit → 256M or 512M
  
  
• max_execution_time → 300
  
  
• max_input_time → 300
  

Restart FPM/Apache after saving.

✅ 2. Fix Permissions
Sometimes Plesk blocks writes.

Set correct permissions for:
/wp-content/themes/

Recommended:

• Folders → 755
  
  
• Files → 644
  

✅ 3. Check Error Logs
Plesk logs will tell you the exact cause:
Plesk → Logs → error_log

Look for:

• ModSecurity blocks
  
  
• PHP fatal errors
  
  
• Timeouts
  
  
• Permission denied errors
  

If ModSecurity is blocking, disable it temporarily for the domain:
Plesk → Domains → Web Application Firewall → Off

✅ 4. Use Theme Upload via cPanel + WP CLI (Most Reliable)
Upload the zip to:
/wp-content/themes/
and then run:


unzip theme.zip

Or via WP-CLI:


wp theme install theme.zip --activate

⚠️ 5. Internal Server Error = Server-Side Issue
It usually indicates:

• Missing PHP modules
  
  
• Low memory
  
  
• Corrupted .htaccess
  
  
• ModSecurity blocks
  

You can also reset .htaccess by resaving permalinks in WordPress.

⭐ If you still face issues...
You may need a developer to troubleshoot your Plesk + WordPress configuration properly.