Update wordpress-upload-limits.md (#22)

Improve grammar and add a section to deal with 502 errors on admin-ajax.php call.s

content/guides/wordpress-upload-limits.md

@@ -7,17 +7,17 @@ video: ''
 
 <you-tube video="rxQMMvvsNS8"></you-tube>
 
-PHP has a 2mb upload limit. This is often not enough for some things you want to do with WordPress and may inhibit plugin installation. 
-To change this, you'll need to make configuration updates to both PHP and NGINX. 
+PHP has a `2mb` upload limit. This is often insufficient for some things you want to do with WordPress and may inhibit plugin installation. 
+To change this, you must make configuration updates to both PHP and NGINX. 
 
 <base-info>
-This is often a standard task for WordPress sites. However, these instructions also apply for any PHP app where you might need
+This is often a standard task for WordPress sites. However, these instructions also apply to any PHP app where you might need
 to modify file upload limits. 
 </base-info>
 
 ## PHP configurations
 
-In the server > services > PHP settings section (click the wrench icon), you can increase the upload limits, you will likely want 
+In the server > services > PHP settings section (click the wrench icon), you can increase the upload limits, and you will likely want 
 to increase the max_input_time, upload_max_filesize, and memory_limit variables. 
 
 Such as:
@@ -34,6 +34,29 @@ After updating PHP, go back to the services section and select the wrench icon f
 2. Save file
 3. Restart nginx by clicking on the restart icon
 
-This then should allow you to upload larger file sizes to your WordPress site. If you are curious as to if the configs 
-were updated and to what other configs you might want to alter for your WordPress site, Wordpress has a section that displays 
+This should allow you to upload larger file sizes to your WordPress site. If you are curious whether the configs 
+were updated and what other configs you might want to alter for your WordPress site. WordPress has a section that displays 
 current configs located in the `WordPress admin dashboard > tools > site health > info > server tab.`
+
+## 502 Errors When Calling `wp-admin/admin-ajax.php`
+
+Some themes and plugins rely heavily on AJAX requests, which can sometimes cause `502` errors when `wp-admin/admin-ajax.php` is called. To attempt to fix this, add the following into the `http` section of your `/etc/nginx/nginx.conf`.
+
+1. Navigate to Server > [The server you want to update] > Services > Nginx.
+2. Click the three dots on the far right and open the menu.
+3. Select `Edit nginx.conf`
+4. In the `http` section, add:
+```
+   ##
+   # FastCGI Settings
+   ##
+   fastcgi_temp_file_write_size 10m;
+   fastcgi_busy_buffers_size 512k;
+   fastcgi_buffer_size 512k;
+   fastcgi_buffers 16 512k;
+```
+5. Click `Update`
+6. Click the three dots on the far right to reopen the Nginx menu.
+7. Select `Restart`.
+
+Once you reload the page generating the error and try again, you should not see the `502` error.