Magento – Magento 2.2.3 Internal Server Error: Read timed out after 10 seconds

I have a magento 2.2.3 shop that is throwing me an internal server error every time I try to edit or create a new product. When I click save, it loads for about 10 seconds this shows internal server error. Try again later. I checked the system.log file and it shows the following error:

[2018-04-09 21:36:38] main.CRITICAL: Read timed out after 10 seconds  {"method":"POST","url":"https://custombuttons97.com/admin_cfytnh/catalog/product/save/id/5/type/simple/store/0/set/12/key/923d4f492fbf22029126adee53137102bd09deee49d3bdb1f83885e9ca3c4853/back/edit","invalidateInfo":{"server":"[object] (Zend\\Uri\\Uri: http://127.0.0.1:6082/)","tagsPattern":"((^|,)cat_p_5(,|$))"}} []

What would cause this issue and how can I fix it?

UPDATE:

I modified the file vendor/magento/module-cache-invalidate/Model/PurgeCache.php I changed the timeout to 90 seconds and I am now getting an error of timed out after 90 seconds. See below:

[2018-04-10 18:45:11] main.CRITICAL: Read timed out after 90 seconds {"method":"POST","url":"https://custombuttons97.com/admin_cfytnh/catalog/product/save/id/5/type/simple/store/0/set/12/key/8937840148454054d5ff7ae2ff947a60b2b477567a535f0c1b649b69c06bdc23/back/edit","invalidateInfo":{"server":"[object] (Zend\\Uri\\Uri: http://127.0.0.1:6082/)","tagsPattern":"((^|,)cat_p_5(,|$))"}} []
[2018-04-10 18:45:18] main.CRITICAL: A valid response status line was not found in the provided string {"method":"POST","url":"https://custombuttons97.com/admin_cfytnh/catalog/product/save/id/5/type/simple/store/0/set/12/key/8937840148454054d5ff7ae2ff947a60b2b477567a535f0c1b649b69c06bdc23/back/edit","invalidateInfo":{"server":"[object] (Zend\\Uri\\Uri: http://127.0.0.1:6082/)","tagsPattern":"((^|,)cat_p_5(,|$))"}} []
[2018-04-10 18:45:22] main.INFO: Broken reference: the 'product.reviews' element cannot be added as child to 'product_tabs', because the latter doesn't exist [] []