<p>I'm guessing the site you're setting up on the subdomain is on a new server?</p>

<blockquote>
  <p>Craft CMS requires the PHP multibyte string extension in order to run.</p>
</blockquote>

<p>That error means that the PHP <a href="https://secure.php.net/manual/en/book.mbstring.php" rel="nofollow noreferrer">multibyte extension</a> isn't installed or enabled on your server and both Craft 2 and Craft 3 require it. </p>

CC BY-SA 4.0
2018-12-17T16:30:28.737Z
Thanks for your reply!  It's actually on the same server - just a new subdomain.  I will check with our host and make sure it is setup.   I can move the website to the original domain and it works, its just when I move it to the subdomain.  I'll update with results from host.  Thanks for your help.
MikeyB
CC BY-SA 4.0
2022-12-26T12:08:27.660Z
It's possible each subdomain has its own `php.ini` and the new one doesn't have `extension=mbstring.so`
Capsule
CC BY-SA 4.0
2018-12-15T02:09:26.067Z
2018-12-15T02:09:26.067Z
Brad Bell
<p>I am moving our current site to a subdomain and get this: "Craft CMS requires the PHP multibyte string extension in order to run."</p>

<p>I have updated the <code>$craftPath</code> variable and <code>System-&gt;General-&gt;SiteUrl</code> CP setting to the updated URL.</p>

<p>Am I missing something?</p>

<siteurl>
Moving site to subdomain
# Moving site to subdomain

(Asked by: username_0 on 2018-12-14)

I am moving our current site to a subdomain and get this: "Craft CMS requires the PHP multibyte string extension in order to run."

I have updated the `$craftPath` variable and `System->General->SiteUrl` CP setting to the updated URL.

Am I missing something?

**Tags:** siteurl

---

## 1 answers

### Answer by username_1 on 2018-12-15. Score: 0

I'm guessing the site you're setting up on the subdomain is on a new server?

> Craft CMS requires the PHP multibyte string extension in order to run.

That error means that the PHP [multibyte extension](https://secure.php.net/manual/en/book.mbstring.php) isn't installed or enabled on your server and both Craft 2 and Craft 3 require it.

> **Comments:**
> **username_0**: Thanks for your reply!  It's actually on the same server - just a new subdomain.  I will check with our host and make sure it is setup.   I can move the website to the original domain and it works, its just when I move it to the subdomain.  I'll update with results from host.  Thanks for your help.  
> **username_2**: It's possible each subdomain has its own `php.ini` and the new one doesn't have `extension=mbstring.so`  

---

