fl-builder ver=2.3.2.5:6 SyntaxError: Unexpected token < in JSON

[gtfoplan]

On chrome:
Version 80.0.3987.149 (Official Build) (64-bit)

Received this error:

JQMIGRATE: Migrate is installed, version 1.4.1
connect.facebook.net/en_US/fbevents.js:1 Failed to load resource: net::ERR_BLOCKED_BY_CLIENT
?fl_builder:1 A cookie associated with a cross-site resource at http://vimeo.com/ was set without the `SameSite` attribute. A future release of Chrome will only deliver cookies with cross-site requests if they are set with `SameSite=None` and `Secure`. You can review cookies in developer tools under Application>Storage>Cookies and see more details at https://www.chromestatus.com/feature/5088147346030592 and https://www.chromestatus.com/feature/5633521622188032.
?fl_builder:1 A cookie associated with a cross-site resource at https://vimeo.com/ was set without the `SameSite` attribute. A future release of Chrome will only deliver cookies with cross-site requests if they are set with `SameSite=None` and `Secure`. You can review cookies in developer tools under Application>Storage>Cookies and see more details at https://www.chromestatus.com/feature/5088147346030592 and https://www.chromestatus.com/feature/5633521622188032.
/wp-admin/admin-ajax.php:1 Failed to load resource: net::ERR_NETWORK_IO_SUSPENDED
fl-builder.min.js?ver=2.3.2.5:6 ************************************************************************
fl-builder.min.js?ver=2.3.2.5:6 Beaver Builder caught the following JavaScript error. If Beaver Builder is not functioning as expected the cause is most likely this error. Please help us by disabling all plugins and testing Beaver Builder while reactivating each to determine if the issue is related to a third party plugin.
fl-builder.min.js?ver=2.3.2.5:6 SyntaxError: Unexpected token < in JSON at position 0
    at JSON.parse (<anonymous>)
    at Object._jsonParse (fl-builder.min.js?ver=2.3.2.5:6)
    at Object.renderLegacySettingsComplete (fl-builder.min.js?ver=2.3.2.5:10)
    at Object.<anonymous> (fl-builder.min.js?ver=2.3.2.5:10)
    at Object.success (fl-builder.min.js?ver=2.3.2.5:6)
    at i (jquery.js?ver=1.12.4-wp:2)
    at Object.fireWith [as resolveWith] (jquery.js?ver=1.12.4-wp:2)
    at x (jquery.js?ver=1.12.4-wp:4)
    at XMLHttpRequest.c (jquery.js?ver=1.12.4-wp:4)
fl-builder.min.js?ver=2.3.2.5:6 Debug Info
fl-builder.min.js?ver=2.3.2.5:6 AJAX returned HTML page instead of data. (Possible 404 or max_input_vars)
fl-builder.min.js?ver=2.3.2.5:6 PHP Version: 7.3.14
fl-builder.min.js?ver=2.3.2.5:6 Memory Limit: 256M
fl-builder.min.js?ver=2.3.2.5:6 max_input_vars: 1000
fl-builder.min.js?ver=2.3.2.5:6 modsecfix: Disabled
fl-builder.min.js?ver=2.3.2.5:6 ************************************************************************
DevTools failed to parse SourceMap: chrome-extension://gighmmpiobklfepjocnamgkkbiglidom/include.preload.js.map
DevTools failed to parse SourceMap: chrome-extension://gighmmpiobklfepjocnamgkkbiglidom/include.postload.js.map
DevTools failed to parse SourceMap: https://www.gtfoplan.com/wp-content/themes/reykjavik/library/js/vendors/css-vars-ponyfill/css-vars-ponyfill.min.js.map

Thank you!
Ann

[SergeyBiryukov]

Hi there, welcome to WordPress Trac! Thanks for the ticket.

I'm sorry to hear you are having issues with WordPress. Please note that this Trac is used for enhancements and bug reporting for the WordPress core software, not for individual support questions.

There is no fl-builder.min.js file in core, it appears to be related to the Beaver Builder plugin.

Please try the support forums to get help with your site: ​https://wordpress.org/support/forums/