This block has encountered an error and cannot be previewed.

Hello.

When I try to add a paragraph in a new post or page I get “This block has encountered an error and cannot be previewed.

This block has encountered an error and cannot be previewed.

It appears Tiny MCE is not defined causing a cascade of errors, but only when Gutenberg is activated. Installed WP Troubleshoot, and only enabled Gutenberg editor (all other plugins deactivated) and get these errors in the console.

This happens on all of our websites with Gutenberg, regardless of plugins or themes used. Default themes, Genesis Themes, custom themes… I even tried a fresh WordPress install. Some sites are on Cloudflare, but disabling Cloudflare doesn’t change things.

When I switch back to the old editor (disable Gutenberg) Tiny MCE is defined, and no errors appear.

GET https://…/wp-includes/js/tinymce/wp-tinymce.php?ver=4.9.8 404 (Not Found)
tinymce-plugin-lists.min.137fa94a.js:1 Uncaught ReferenceError: tinymce is not defined
at tinymce-plugin-lists.min.137fa94a.js:1
at tinymce-plugin-lists.min.137fa94a.js:1
(anonymous) @ tinymce-plugin-lists.min.137fa94a.js:1
(anonymous) @ tinymce-plugin-lists.min.137fa94a.js:1
tinymce-plugin-paste.min.f6e82d7a.js:1 Uncaught ReferenceError: tinymce is not defined
at tinymce-plugin-paste.min.f6e82d7a.js:1
at tinymce-plugin-paste.min.f6e82d7a.js:1
(anonymous) @ tinymce-plugin-paste.min.f6e82d7a.js:1
(anonymous) @ tinymce-plugin-paste.min.f6e82d7a.js:1
tinymce-plugin-table.min.3fa6c17e.js:1 Uncaught ReferenceError: tinymce is not defined
at tinymce-plugin-table.min.3fa6c17e.js:1
at tinymce-plugin-table.min.3fa6c17e.js:1
(anonymous) @ tinymce-plugin-table.min.3fa6c17e.js:1
(anonymous) @ tinymce-plugin-table.min.3fa6c17e.js:1
index.js?ver=1534877850:1 Fetch finished loading: GET “https://…/wp-json/wp/v2/users/?who=authors&per_page=-1”.
(anonymous) @ index.js?ver=1534877850:1
t @ index.js?ver=1534877850:1
b @ index.js?ver=1534877850:1
t @ index.js?ver=1534877850:1
m @ index.js?ver=1534877850:1
t @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:1
t @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:1
m @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:1
t @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:1
t @ index.js?ver=1534877850:1
S @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:1
w @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:1
t.(anonymous function) @ index.js?ver=1534877850:1
r @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:1
n @ index.js?ver=1534877850:1
_invoke @ index.js?ver=1534877850:1
u.next @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:1
w @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:1
t.(anonymous function) @ index.js?ver=1534877850:1
o @ index.js?ver=1534877850:1
c @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:1
n @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:1
p @ index.js?ver=1534877850:1
f @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:12
r @ index.js?ver=1534877850:1
e @ index.js?ver=1534877850:1
yh @ react-dom.min.82e21c65.js:97
lg @ react-dom.min.82e21c65.js:120
mg @ react-dom.min.82e21c65.js:120
gc @ react-dom.min.82e21c65.js:127
vb @ react-dom.min.82e21c65.js:126
ub @ react-dom.min.82e21c65.js:126
zd @ react-dom.min.82e21c65.js:124
ra @ react-dom.min.82e21c65.js:123
enqueueSetState @ react-dom.min.82e21c65.js:189
q.setState @ react.min.ab6b06d4.js:18
(anonymous) @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:1
d @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:1
w @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:1
t.(anonymous function) @ index.js?ver=1534877850:1
o @ index.js?ver=1534877850:1
c @ index.js?ver=1534877850:1
Promise.then (async)
o @ index.js?ver=1534877850:1
c @ index.js?ver=1534877850:1
Promise.then (async)
o @ index.js?ver=1534877850:1
c @ index.js?ver=1534877850:1
Promise.then (async)
o @ index.js?ver=1534877850:1
c @ index.js?ver=1534877850:1
Promise.then (async)
o @ index.js?ver=1534877850:1
c @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:1
n @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:1
p @ index.js?ver=1534877850:1
f @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:1
(anonymous) @ index.js?ver=1534877850:12
r @ index.js?ver=1534877850:1
e @ index.js?ver=1534877850:1
yh @ react-dom.min.82e21c65.js:97
lg @ react-dom.min.82e21c65.js:120
mg @ react-dom.min.82e21c65.js:120
gc @ react-dom.min.82e21c65.js:127
vb @ react-dom.min.82e21c65.js:126
ub @ react-dom.min.82e21c65.js:126
zd @ react-dom.min.82e21c65.js:124
ra @ react-dom.min.82e21c65.js:123
Id @ react-dom.min.82e21c65.js:138
kc @ react-dom.min.82e21c65.js:138
Sa.render @ react-dom.min.82e21c65.js:194
(anonymous) @ react-dom.min.82e21c65.js:141
Hd @ react-dom.min.82e21c65.js:136
mc @ react-dom.min.82e21c65.js:141
render @ react-dom.min.82e21c65.js:196
Dn @ index.js?ver=1534877850:12
(anonymous) @ post-new.php?post_type=page:2877
react-dom.min.82e21c65.js:110 TypeError: Cannot read property ‘init’ of undefined
at t.value (index.js?ver=1534877850:12)
at t.value (index.js?ver=1534877850:12)
at jc (react-dom.min.82e21c65.js:134)
at gc (react-dom.min.82e21c65.js:127)
at vb (react-dom.min.82e21c65.js:126)
at ub (react-dom.min.82e21c65.js:126)
at wg (react-dom.min.82e21c65.js:137)
at Ze (react-dom.min.82e21c65.js:41)