Mike Meinz

After further research, I found that a row in wp_posts that was the definition of a ACF Text field for a link_url contained a malformed URL in the post_content column. The URL value in the post_content serialized string should have been empty.

I modified the ACF field by adding a text length limit in Edit Field Group and saved it. That regenerated the post_content column in the database eliminating the malformed URL. That solved the problem.

Solved. Thank You.

add_action('acf/init', 'my_acf_init');
function my_acf_init() {
    /* ACF Widget Titles */
    add_filter( 'show_acfw_titles', '__return_true' );

    /* Sitewide Theme Options Page - ACF */
    if( function_exists('acf_add_options_page') ) {
	acf_add_options_page();
    }
}

I found that the Mini Calendar navigation buttons work as expected when the Mini Calendar is the only My Calendar shortcode on the page.

This is what my HTML looks like when the Mini Calendar navigation buttons aren’t working:

<div class="calendar" style="display:flex;flex-wrap:wrap;flex-direction:row;">
<div class="grid" style="flex:50%;"> 
[my_calendar format="mini" time="month" above="nav" below="none"]
</div>
<div class="eventlist" style="flex:50%;"> 
<h2>Upcoming Events</h2>
[my_calendar_upcoming fallback="No events scheduled." template="{date}, {time}: {linking_title}" type="event" before="0" after="3" order="asc"]
<a href="<?php echo bloginfo('url'); ?>/news-and-events/calendar/" class="button">More Events ></a>
</div>
</div>

When I remove the second My Calendar short code, the Mini Calendar navigation buttons work as expected.

<div class="calendar" style="display:flex;flex-wrap:wrap;flex-direction:row;">
<div class="grid" style="flex:50%;"> 
[my_calendar format="mini" time="month" above="nav" below="none"]
</div>
</div>

No more errors in the error_log..

Thanks

Previous posts have been about my live site running at GoDaddy. This time, I tried on a WAMP64 instance on my PC. I get the following errors in the PHP error_log. I don’t understand why these did not appear in my live site error_log. Wondering if an Action Hook should be used in your plugin instead of directly calling wp_ functions.

[24-Nov-2025 15:27:33 UTC] PHP Warning: Cannot modify header information - headers already sent by (output started at C:\wamp64\www\zzzzzzzz.com\wp-content\plugins\acf-widgets\includes\helper-functions.php:119) in C:\wamp64\www\zzzzzzzz.com\wp-includes\pluggable.php on line 1108
[24-Nov-2025 15:27:33 UTC] PHP Stack trace:
[24-Nov-2025 15:27:33 UTC] PHP 1. {main}() C:\wamp64\www\zzzzzzzz.com\wp-login.php:0
[24-Nov-2025 15:27:33 UTC] PHP 2. do_action($hook_name = 'login_form') C:\wamp64\www\zzzzzzzz.com\wp-login.php:1534
[24-Nov-2025 15:27:33 UTC] PHP 3. WP_Hook->do_action($args = [0 => '']) C:\wamp64\www\zzzzzzzz.com\wp-includes\plugin.php:517
[24-Nov-2025 15:27:33 UTC] PHP 4. WP_Hook->apply_filters($value = '', $args = [0 => '']) C:\wamp64\www\zzzzzzzz.com\wp-includes\class-wp-hook.php:348
[24-Nov-2025 15:27:33 UTC] PHP 5. ThemePaste\SecureAdmin\Classes\Features\TwoFactorAuth->check_otp_submission('') C:\wamp64\www\zzzzzzzz.com\wp-includes\class-wp-hook.php:324
[24-Nov-2025 15:27:33 UTC] PHP 6. wp_set_auth_cookie($user_id = 42, $remember = TRUE, $secure = uninitialized, $token = uninitialized) C:\wamp64\www\zzzzzzzz.com\wp-content\plugins\admin-safety-guard\app\Classes\Features\TwoFactorAuth.php:165
[24-Nov-2025 15:27:33 UTC] PHP 7. setcookie($name = 'wordpress_sec_4de907315fc2b36622a37ab04494c117', $value = 'meinz|1769182053|t2BnCW5jehAnjtZBMEsuHo4ON9fyjpTtgU4afb6nN5R|b224462be7869770cb5e53089da63bcb0e2754613b8a3e6d22b012ad47b7a987', $expires_or_options = 1769225253, $path = '/wp-content/plugins', $domain = '', $secure = TRUE, $httponly = TRUE) C:\wamp64\www\zzzzzzzz.com\wp-includes\pluggable.php:1108
[24-Nov-2025 15:27:33 UTC] PHP Warning: Cannot modify header information - headers already sent by (output started at C:\wamp64\www\zzzzzzzz.com\wp-content\plugins\acf-widgets\includes\helper-functions.php:119) in C:\wamp64\www\zzzzzzzz.com\wp-includes\pluggable.php on line 1109
[24-Nov-2025 15:27:33 UTC] PHP Stack trace:
[24-Nov-2025 15:27:33 UTC] PHP 1. {main}() C:\wamp64\www\zzzzzzzz.com\wp-login.php:0
[24-Nov-2025 15:27:33 UTC] PHP 2. do_action($hook_name = 'login_form') C:\wamp64\www\zzzzzzzz.com\wp-login.php:1534
[24-Nov-2025 15:27:33 UTC] PHP 3. WP_Hook->do_action($args = [0 => '']) C:\wamp64\www\zzzzzzzz.com\wp-includes\plugin.php:517
[24-Nov-2025 15:27:33 UTC] PHP 4. WP_Hook->apply_filters($value = '', $args = [0 => '']) C:\wamp64\www\zzzzzzzz.com\wp-includes\class-wp-hook.php:348
[24-Nov-2025 15:27:33 UTC] PHP 5. ThemePaste\SecureAdmin\Classes\Features\TwoFactorAuth->check_otp_submission('') C:\wamp64\www\zzzzzzzz.com\wp-includes\class-wp-hook.php:324
[24-Nov-2025 15:27:33 UTC] PHP 6. wp_set_auth_cookie($user_id = 42, $remember = TRUE, $secure = uninitialized, $token = uninitialized) C:\wamp64\www\zzzzzzzz.com\wp-content\plugins\admin-safety-guard\app\Classes\Features\TwoFactorAuth.php:165
[24-Nov-2025 15:27:33 UTC] PHP 7. setcookie($name = 'wordpress_sec_4de907315fc2b36622a37ab04494c117', $value = 'meinz|1769182053|t2BnCW5jehAnjtZBMEsuHo4ON9fyjpTtgU4afb6nN5R|b224462be7869770cb5e53089da63bcb0e2754613b8a3e6d22b012ad47b7a987', $expires_or_options = 1769225253, $path = '/wp-admin', $domain = '', $secure = TRUE, $httponly = TRUE) C:\wamp64\www\zzzzzzzz.com\wp-includes\pluggable.php:1109
[24-Nov-2025 15:27:33 UTC] PHP Warning: Cannot modify header information - headers already sent by (output started at C:\wamp64\www\zzzzzzzz.com\wp-content\plugins\acf-widgets\includes\helper-functions.php:119) in C:\wamp64\www\zzzzzzzz.com\wp-includes\pluggable.php on line 1110
[24-Nov-2025 15:27:33 UTC] PHP Stack trace:
[24-Nov-2025 15:27:33 UTC] PHP 1. {main}() C:\wamp64\www\zzzzzzzz.com\wp-login.php:0
[24-Nov-2025 15:27:33 UTC] PHP 2. do_action($hook_name = 'login_form') C:\wamp64\www\zzzzzzzz.com\wp-login.php:1534
[24-Nov-2025 15:27:33 UTC] PHP 3. WP_Hook->do_action($args = [0 => '']) C:\wamp64\www\zzzzzzzz.com\wp-includes\plugin.php:517
[24-Nov-2025 15:27:33 UTC] PHP 4. WP_Hook->apply_filters($value = '', $args = [0 => '']) C:\wamp64\www\zzzzzzzz.com\wp-includes\class-wp-hook.php:348
[24-Nov-2025 15:27:33 UTC] PHP 5. ThemePaste\SecureAdmin\Classes\Features\TwoFactorAuth->check_otp_submission('') C:\wamp64\www\zzzzzzzz.com\wp-includes\class-wp-hook.php:324
[24-Nov-2025 15:27:33 UTC] PHP 6. wp_set_auth_cookie($user_id = 42, $remember = TRUE, $secure = uninitialized, $token = uninitialized) C:\wamp64\www\zzzzzzzz.com\wp-content\plugins\admin-safety-guard\app\Classes\Features\TwoFactorAuth.php:165
[24-Nov-2025 15:27:33 UTC] PHP 7. setcookie($name = 'wordpress_logged_in_4de907315fc2b36622a37ab04494c117', $value = 'meinz|1769182053|t2BnCW5jehAnjtZBMEsuHo4ON9fyjpTtgU4afb6nN5R|8b8c6209165da687ada6a91f7a2fadd769e837fc7ecf5e94268b23090a094951', $expires_or_options = 1769225253, $path = '/', $domain = '', $secure = TRUE, $httponly = TRUE) C:\wamp64\www\zzzzzzzz.com\wp-includes\pluggable.php:1110
[24-Nov-2025 15:27:33 UTC] PHP Warning: Cannot modify header information - headers already sent by (output started at C:\wamp64\www\zzzzzzzz.com\wp-content\plugins\acf-widgets\includes\helper-functions.php:119) in C:\wamp64\www\zzzzzzzz.com\wp-includes\pluggable.php on line 1450
[24-Nov-2025 15:27:33 UTC] PHP Stack trace:
[24-Nov-2025 15:27:33 UTC] PHP 1. {main}() C:\wamp64\www\zzzzzzzz.com\wp-login.php:0
[24-Nov-2025 15:27:33 UTC] PHP 2. do_action($hook_name = 'login_form') C:\wamp64\www\zzzzzzzz.com\wp-login.php:1534
[24-Nov-2025 15:27:33 UTC] PHP 3. WP_Hook->do_action($args = [0 => '']) C:\wamp64\www\zzzzzzzz.com\wp-includes\plugin.php:517
[24-Nov-2025 15:27:33 UTC] PHP 4. WP_Hook->apply_filters($value = '', $args = [0 => '']) C:\wamp64\www\zzzzzzzz.com\wp-includes\class-wp-hook.php:348
[24-Nov-2025 15:27:33 UTC] PHP 5. ThemePaste\SecureAdmin\Classes\Features\TwoFactorAuth->check_otp_submission('') C:\wamp64\www\zzzzzzzz.com\wp-includes\class-wp-hook.php:324
[24-Nov-2025 15:27:33 UTC] PHP 6. wp_redirect($location = 'https://zzzzzzzz.com/wp-admin/', $status = uninitialized, $x_redirect_by = uninitialized) C:\wamp64\www\zzzzzzzz.com\wp-content\plugins\admin-safety-guard\app\Classes\Features\TwoFactorAuth.php:168
[24-Nov-2025 15:27:33 UTC] PHP 7. header($header = 'X-Redirect-By: WordPress') C:\wamp64\www\zzzzzzzz.com\wp-includes\pluggable.php:1450
[24-Nov-2025 15:27:33 UTC] PHP Warning: Cannot modify header information - headers already sent by (output started at C:\wamp64\www\zzzzzzzz.com\wp-content\plugins\acf-widgets\includes\helper-functions.php:119) in C:\wamp64\www\zzzzzzzz.com\wp-includes\pluggable.php on line 1453
[24-Nov-2025 15:27:33 UTC] PHP Stack trace:
[24-Nov-2025 15:27:33 UTC] PHP 1. {main}() C:\wamp64\www\zzzzzzzz.com\wp-login.php:0
[24-Nov-2025 15:27:33 UTC] PHP 2. do_action($hook_name = 'login_form') C:\wamp64\www\zzzzzzzz.com\wp-login.php:1534
[24-Nov-2025 15:27:33 UTC] PHP 3. WP_Hook->do_action($args = [0 => '']) C:\wamp64\www\zzzzzzzz.com\wp-includes\plugin.php:517
[24-Nov-2025 15:27:33 UTC] PHP 4. WP_Hook->apply_filters($value = '', $args = [0 => '']) C:\wamp64\www\zzzzzzzz.com\wp-includes\class-wp-hook.php:348
[24-Nov-2025 15:27:33 UTC] PHP 5. ThemePaste\SecureAdmin\Classes\Features\TwoFactorAuth->check_otp_submission('') C:\wamp64\www\zzzzzzzz.com\wp-includes\class-wp-hook.php:324
[24-Nov-2025 15:27:33 UTC] PHP 6. wp_redirect($location = 'https://zzzzzzzz.com/wp-admin/', $status = uninitialized, $x_redirect_by = uninitialized) C:\wamp64\www\zzzzzzz.com\wp-content\plugins\admin-safety-guard\app\Classes\Features\TwoFactorAuth.php:168
[24-Nov-2025 15:27:33 UTC] PHP 7. header($header = 'Location: https://zzzzzzzz.com/wp-admin/', $replace = TRUE, $response_code = 302) C:\wamp64\www\zzzzzzz.com\wp-includes\pluggable.php:1453

I believe that I have found the problem.

In your TwoFactorAuth.php file at line 163 this wp_set_auth_cookie( $user_id ); sets the logged_in cookie. It is missing the $remember parameter. Also, missing the $token parameter. That causes a session cookie to be set instead of a persistent cookie with an expiration date.

See https://developer.wordpress.org/reference/functions/wp_set_auth_cookie/
wp_set_auth_cookie( int $user_id, bool $remember = false, bool|string $secure = ”, string $token = ” )

I just checked the wp-admin error_log. Today is 09/20. The reported SQL syntax errors were logged on 09/12. I thought you should be aware that SQL syntax error has not been repeated at this time.