Your wordpress site may report http 503 errror, there are some reasons that may cause this error. However, in this tutorial, we will discuss one reason.
How does 503 error occur?
When you open a web page by your browser and find site reports 503 service unavailable error. You login into your wordpress site, then open this page again, you find this page is ok. How to fix?
How to fix 503 error?
As to problem above, the main reason is there is something wrong with your wordpress cache plugin. You can:
1. Delete the cache of this page
2. Activate a different wordpress cache plugin, such as WP Super Cache.