Cannot view single post recieve error 404

Debug info incase you need it:

### Begin Custom Post Type UI Debug Info ###

		Multisite:                No

		SITE_URL:                 https://auroradesign.net.au
		HOME_URL:                 https://auroradesign.net.au

		WordPress Version:        4.5.3
		Permalink Structure:      /%postname%/
		Active Theme:             Aurora 1.0

		Registered Post Types:    post, page, attachment, revision, nav_menu_item, projects, wysijap, ml-slider

		PHP Version:              5.3.29
		MySQL Version:            5.5.48
		Web Server Info:          Apache/2.2.31 (Unix) mod_ssl/2.2.31 OpenSSL/1.0.1e-fips mod_bwlimited/1.4

		Show On Front:            posts
		Page On Front:             (#0)
		Page For Posts:            (#0)

		WordPress Memory Limit:   40MB

		TOTAL PLUGINS: 11

		ACTIVE PLUGINS: (8)

		Akismet: 3.1.11
		Custom Field Template: 2.3.7
		Custom Post Type UI: 1.3.5
		MailPoet Newsletters: 2.7.2
		Meta Slider: 3.3.7
		Simple Fields: 1.4.11
		WP Realtime Sitemap: 1.5.4
		WP Sitemap: 1.0

		INACTIVE PLUGINS: (3)

		Projects 3.0: 1.0
		Quick Page/Post Redirect Plugin: 5.1.8
		WP Backup Plugin: 1.2

		Post Types:
		{"projects":{"name":"projects","label":"Projects","singular_label":"Project ","description":"List of all projects","public":"true","show_ui":"true","show_in_nav_menus":"true","show_in_rest":"false","rest_base":"","has_archive":"false","has_archive_string":"","exclude_from_search":"false","capability_type":"post","hierarchical":"false","rewrite":"true","rewrite_slug":"","rewrite_withfront":"true","query_var":"true","query_var_slug":"","menu_position":"","show_in_menu":"true","show_in_menu_string":"","menu_icon":"","supports":["title","editor","thumbnail","excerpt","page-attributes"],"taxonomies":["category","post_tag","projectcategories"],"labels":{"menu_name":"","all_items":"","add_new":"","add_new_item":"","edit_item":"","new_item":"","view_item":"","search_items":"","not_found":"","not_found_in_trash":"","parent":"","featured_image":"","set_featured_image":"","remove_featured_image":"","use_featured_image":"","archives":"","insert_into_item":"","uploaded_to_this_item":"","filter_items_list":"","items_list_navigation":"","items_list":""},"custom_supports":""}}

		Taxonomies:
		{"projectcategories":{"name":"projectcategories","label":"Project Categories","singular_label":"Project Category","description":"","public":"true","hierarchical":"true","show_ui":"true","query_var":"true","query_var_slug":"","rewrite":"true","rewrite_slug":"projects","rewrite_withfront":"1","rewrite_hierarchical":"0","show_admin_column":"false","show_in_rest":"false","show_in_quick_edit":"","rest_base":"","labels":{"menu_name":"","all_items":"","edit_item":"","view_item":"","update_item":"","add_new_item":"","new_item_name":"","parent_item":"","parent_item_colon":"","search_items":"","popular_items":"","separate_items_with_commas":"","add_or_remove_items":"","choose_from_most_used":"","not_found":"","no_terms":"","items_list_navigation":"","items_list":""},"object_types":["projects"]}}

		### End Debug Info ###

Looks like you have the post type slug being “projects” and then also your custom taxonomy with a rewrite slug being “projects” as well. I was able to recreate once I imported both, and once I renamed the taxonomy rewrite to something else, the 404 error cleared itself up.

Chances are both post type and taxonomy query args are being mixed up due to this match, and thus WordPress just isn’t finding anything to match.