Title: Error: Call to undefined method Symfony\Polyfill\Mbstring Last modified: February 5, 2020 --- # Error: Call to undefined method Symfony\Polyfill\Mbstring * Resolved [Music365](https://wordpress.org/support/users/clairporium/) * (@clairporium) * [6 years, 4 months ago](https://wordpress.org/support/topic/error-call-to-undefined-method-symfonypolyfillmbstring/) * Hi Paul, * I updated Shield on Tuesday, and today I am getting a ‘Fatal error: Uncaught Error’ when trying to login. * Below is the basic gist of the error. I removed the site directory info, as noted in brackets [ ], but the rest should be enough, I think, to give you an idea of what is happening. * Fatal error: Uncaught Error: Call to undefined method Symfony\Polyfill\Mbstring\ Mbstring::mb_ord() in [removed site directory info] wp-content/plugins/wp-simple- firewall/src/lib/vendor/symfony/polyfill-mbstring/bootstrap.php:55 Stack trace:# 0 * [removed site directory info]/wp-content/plugins/wp-simple-firewall/src/lib/custom/ mkopinsky/zxcvbn-php/src/Matcher.php(25): ZxcvbnPhp56\Matchers\SequenceMatch:: match(‘505’, Array) #2 * [removed site directory info]/wp-content/plugins/wp-simple-firewall/src/lib/custom/ mkopinsky/zxcvbn-php/src/Matchers/RepeatMatch.php(60): ZxcvbnPhp56\Matcher->getMatches(‘ 505’) #3 * [removed site directory info]/wp-content/plugins/wp-simple-firewall/src/lib/custom/ mkopinsky/zxcvbn-php/src/Matcher.php(25): ZxcvbnPhp56\Matchers\RepeatMatch::match[ password & site info removed] wp-content/plugins/wp-simple-firewall/src/lib/vendor/ symfony/polyfill-mbstring/bootstrap.php on line 55 * Any idea what is happening? My PHP version is 7.1. * Appreciate your time and assistance. * -M Viewing 10 replies - 1 through 10 (of 10 total) * Plugin Author [Paul](https://wordpress.org/support/users/paultgoodchild/) * (@paultgoodchild) * [6 years, 4 months ago](https://wordpress.org/support/topic/error-call-to-undefined-method-symfonypolyfillmbstring/#post-12403375) * Hi, * Interestingly, this seems to be a similar problem to the recent thread here, but for another library: [https://wordpress.org/support/topic/php-error-message-on-one-site/](https://wordpress.org/support/topic/php-error-message-on-one-site/) * Basically, you’re running another plugin which also includes this library, but it’s out of date. It might be difficult to find which plugin it is, but you can deactivate and test 1 plugin at a time to see which plugin, when deactivated, the error disappears. * We’re considering options to help mitigate this problem in the future, but it’s a difficult one for sure… * Thread Starter [Music365](https://wordpress.org/support/users/clairporium/) * (@clairporium) * [6 years, 4 months ago](https://wordpress.org/support/topic/error-call-to-undefined-method-symfonypolyfillmbstring/#post-12406456) * Hi Paul, * Thank you for the info. * I was able to determine that the plugin in question is IMPress for IDX Broker[ https://wordpress.org/plugins/idx-broker-platinum/], but I can’t disable that one because it is a necessary plugin for the website. * I’ll reach out to the IMPress for IDX Broker plugin developer, but not sure how this could be resolved if that plugin and Shield both need symfony/polyfill-mbstring/ bootstrap.php in order to work. * Any thoughts/ideas? * Thank you * -M * Plugin Author [Paul](https://wordpress.org/support/users/paultgoodchild/) * (@paultgoodchild) * [6 years, 4 months ago](https://wordpress.org/support/topic/error-call-to-undefined-method-symfonypolyfillmbstring/#post-12406681) * You can try out our test to work around this problem by replacing the contents of the file `icwp-wpsf.php` which is in the root of your Shield plugin direcotry: * Using a file manager tool and file editor, do the following: 1) download a backup of the file `plugins/wp-simple-firewall/icwp-wpsf.php` 2) make a copy of the file and open it up in a text editor and delete all the content. 3) Go here: [https://github.com/FernleafSystems/Shield-Security-for-WordPress/blob/develop/icwp-wpsf.php](https://github.com/FernleafSystems/Shield-Security-for-WordPress/blob/develop/icwp-wpsf.php) 4) Click on the Raw button 5) Select all the text on this page and paste it into the file created in step 2). 6) Save the file 7) upload the file to the same place you downloaded it from in step 1) * Let us know if this solves your problem. * Of course, if there’s any problems caused by this, you can restore the backup of the file you created in step 1). * Thanks. * Thread Starter [Music365](https://wordpress.org/support/users/clairporium/) * (@clairporium) * [6 years, 4 months ago](https://wordpress.org/support/topic/error-call-to-undefined-method-symfonypolyfillmbstring/#post-12406764) * Paul, * Thanks, I tried your suggestion, but it did not work. Below is the new error message with site directory info removed, as noted in brackets [ ]. * Fatal error: Uncaught Error: Call to undefined function ZxcvbnPhp56\Matchers\ mb_ord() in /[removed site directory info]/wp-content/plugins/wp-simple-firewall/ src/lib/custom/mkopinsky/zxcvbn-php/src/Matchers/SequenceMatch.php:40 Stack trace:# 0 /[removed site directory info]/wp-content/plugins/wp-simple-firewall/src/lib/ custom/mkopinsky/zxcvbn-php/src/Matcher.php(25): ZxcvbnPhp56\Matchers\SequenceMatch:: match(‘505’, Array) #1 /[removed site directory info]/wp-content/plugins/wp-simple- firewall/src/lib/custom/mkopinsky/zxcvbn-php/src/Matchers/RepeatMatch.php(60): ZxcvbnPhp56\Matcher->getMatches(‘505’) #2 /[removed site directory info]/wp-content/ plugins/wp-simple-firewall/src/lib/custom/mkopinsky/zxcvbn-php/src/Matcher.php( 25): ZxcvbnPhp56\Matchers\RepeatMatch::match(‘[removed password info]…’, Array)# 3 /[removed site directory info]/wp-content/plugins/wp-simple-firewall/src/lib/ custom/mkopinsky/zxcvbn-php/src/Zxcvbn.php(66): ZxcvbnPhp56\Matcher in /[removed site directory info]/wp-content/plugins/wp-simple-firewall/src/lib/custom/mkopinsky/ zxcvbn-php/src/Matchers/SequenceMatch.php on line 40 * So, while I wait for the folks over at IDX Broker to get back to me. I am wondering about the Shield specific references in the error message that mention /wp-simple- firewall/src/lib/custom/mkopinsky…. * If IDX Broker updates bootstrap.php located here lib/vendor/symfony/polyfill- mbstring/bootstrap.php — will that sort out the above? * Thanks, -M * Plugin Author [Paul](https://wordpress.org/support/users/paultgoodchild/) * (@paultgoodchild) * [6 years, 4 months ago](https://wordpress.org/support/topic/error-call-to-undefined-method-symfonypolyfillmbstring/#post-12406840) * The other alternative is to turn off password strength metering within Shield/ User Management… * As to whether upgrading the other library will fix this, or not, I don’t know. I should imagine it would… - This reply was modified 6 years, 4 months ago by [Paul](https://wordpress.org/support/users/paultgoodchild/). Reason: my explanation was wrong * Thread Starter [Music365](https://wordpress.org/support/users/clairporium/) * (@clairporium) * [6 years, 4 months ago](https://wordpress.org/support/topic/error-call-to-undefined-method-symfonypolyfillmbstring/#post-12406899) * Paul, * I only have Enable Password Policies and Prevent Pwned Passwords enabled because I’m using the free version of the plugin, so I can’t do anything about the password strength. * – M * Plugin Author [Paul](https://wordpress.org/support/users/paultgoodchild/) * (@paultgoodchild) * [6 years, 4 months ago](https://wordpress.org/support/topic/error-call-to-undefined-method-symfonypolyfillmbstring/#post-12407018) * Ahh good point. I’ll ensure that these libraries don’t get a look-in if it’s not relevant, for the next release. * It doesn’t address the underlying problem however. I looked up that plugin – looks like that code is around 4 years old. * Until then, you can disable the password policies option altogether to prevent the errors. * Thread Starter [Music365](https://wordpress.org/support/users/clairporium/) * (@clairporium) * [6 years, 4 months ago](https://wordpress.org/support/topic/error-call-to-undefined-method-symfonypolyfillmbstring/#post-12407087) * Thanks, Paul. * Turning off the Password Policies option solved the issue for now. * -M * Plugin Author [Paul](https://wordpress.org/support/users/paultgoodchild/) * (@paultgoodchild) * [6 years, 4 months ago](https://wordpress.org/support/topic/error-call-to-undefined-method-symfonypolyfillmbstring/#post-12409443) * I was just thinking, do you have the `mbstring` extension loaded for your PHP on your webhost? * I just saw that you’re on PHP 7.1 – this problem will likely be resolved if you upgraded your PHP to 7.2 and ensured you have `mbstring` loaded. * The function `mb_ord()` which is failing, [only arrived with PHP 7.2](https://www.php.net/manual/en/function.mb-ord.php). This library that is conflicting is trying to fill-in where `mbstring` isn’t available. So if you upgrade your PHP, you’ll solve the issue. * Thread Starter [Music365](https://wordpress.org/support/users/clairporium/) * (@clairporium) * [6 years, 4 months ago](https://wordpress.org/support/topic/error-call-to-undefined-method-symfonypolyfillmbstring/#post-12415141) * Thanks, Paul. Will give that a try. * Meanwhile, we’ve been thinking about what you said with regards to the plugin code and how old it is, and I think we might end up switching to something else that’s being updated more regularly. * – M Viewing 10 replies - 1 through 10 (of 10 total) The topic ‘Error: Call to undefined method Symfony\Polyfill\Mbstring’ is closed to new replies. * ![](https://ps.w.org/wp-simple-firewall/assets/icon-256x256.png?rev=3054572) * [Shield Security – Smart Bot Blocking, Brute-Force Login Protection & File Scanning](https://wordpress.org/plugins/wp-simple-firewall/) * [Frequently Asked Questions](https://wordpress.org/plugins/wp-simple-firewall/#faq) * [Support Threads](https://wordpress.org/support/plugin/wp-simple-firewall/) * [Active Topics](https://wordpress.org/support/plugin/wp-simple-firewall/active/) * [Unresolved Topics](https://wordpress.org/support/plugin/wp-simple-firewall/unresolved/) * [Reviews](https://wordpress.org/support/plugin/wp-simple-firewall/reviews/) * 10 replies * 2 participants * Last reply from: [Music365](https://wordpress.org/support/users/clairporium/) * Last activity: [6 years, 4 months ago](https://wordpress.org/support/topic/error-call-to-undefined-method-symfonypolyfillmbstring/#post-12415141) * Status: resolved