Error at publishing

[koalahbh]

Expected behaviour and actual behaviour

Save the post content

Steps to reproduce the problem

Edit some part of text making it bold

Specifications

• Browser Name and Version: Chrome Versão 56.0.2924.87 (64-bit)
• WordPress Version: 4.7.2
• Plugin Version: 2.2.1
• Theme name/URL: Flatsome https://themeforest.net/item/flatsome-multipurpose-responsive-woocommerce-theme/5484319

Error messages

Error at chrome console:
wp-content-plugins-wp-front-end-editor-js-fee-2.2.1.js:23 PATCH http://blog.beard.com.br/wp-json/wp/v2/posts/7131 403 (Forbidden)
send @ wp-includes-js-jquery-jquery-1.12.4.js:4
ajax @ wp-includes-js-jquery-jquery-1.12.4.js:4
e.ajax @ wp-includes-js-backbone.min-1.2.3.js:1
e.sync @ wp-includes-js-backbone.min-1.2.3.js:1
sync @ wp-content-plugins-wp-front-end-editor-js-fee-2.2.1.js:23
save @ wp-includes-js-backbone.min-1.2.3.js:1
save @ wp-content-plugins-wp-front-end-editor-js-fee-2.2.1.js:74
onclick @ wp-content-plugins-wp-front-end-editor-js-tinymce.theme-2.2.1.js:168
fire @ wp-content-plugins-wp-front-end-editor-vendor-tinymce-2.2.1.js:24944
fire @ wp-content-plugins-wp-front-end-editor-vendor-tinymce-2.2.1.js:27345
delegate @ wp-content-plugins-wp-front-end-editor-vendor-tinymce-2.2.1.js:27983
executeHandlers @ wp-content-plugins-wp-front-end-editor-vendor-tinymce-2.2.1.js:1168
defaultNativeHandler @ wp-content-plugins-wp-front-end-editor-vendor-tinymce-2.2.1.js:1195
VM93223:1 Uncaught SyntaxError: Unexpected token < in JSON at position 0
at JSON.parse ()
at Object. (wp-content-plugins-wp-front-end-editor-js-fee-2.2.1.js:31)
at Object. (wp-includes-js-jquery-jquery-1.12.4.js:2)
at i (wp-includes-js-jquery-jquery-1.12.4.js:2)
at Object.fireWith [as rejectWith] (wp-includes-js-jquery-jquery-1.12.4.js:2)
at y (wp-includes-js-jquery-jquery-1.12.4.js:4)
at XMLHttpRequest.c (wp-includes-js-jquery-jquery-1.12.4.js:4)