Uncaught InvalidArgumentException: The value "105.148.41.248, 66.249.88.69" is not a valid IP address

[elearningplugins]

Hello. I have some customers receiving a 500 error when trying to purchase through my site. Here's the full exception:

[error] 587#587: *241435 FastCGI sent in stderr: "PHP message: PHP Fatal error: Uncaught InvalidArgumentException: The value "105.148.41.248, 66.249.88.69" is not a valid IP address. in /www/elearningfreak_434/public/wp-content/plugins/gmt-pricing-parity-master/includes/MaxMind-DB-Reader-php/src/MaxMind/Db/Reader.php:104
Stack trace:
#0 /www/elearningfreak_434/public/wp-content/plugins/gmt-pricing-parity-master/includes/helpers.php(294): MaxMind\Db\Reader->get('105.148.41.248,...')
#1 /www/elearningfreak_434/public/wp-content/plugins/gmt-pricing-parity-master/includes/helpers.php(305): gmt_pricing_parity_get_country_by_ip()
#2 /www/elearningfreak_434/public/wp-content/plugins/gmt-pricing-parity-master/includes/checkout.php(40): gmt_pricing_parity_get_country()
#3 /www/elearningfreak_434/public/wp-includes/class-wp-hook.php(298): gmt_pricing_parity_set_discount('')
#4 /www/elearningfreak_434/public/wp-includes/class-wp-hook.php(323): WP_Hook->apply_filters(NULL, Array)
#5 /www/elearningfreak_434/public/wp-includes/plugin.php(453): WP_Hook->do_act" while reading response header from upstream, client: 66.249.88.69, server: www.elearningfreak.com, request: "POST /wp-admin/admin-ajax.php HTTP/1.0", upstream: "fastcgi://unix:/var/run/php7.3-fpm-elearningfreak.sock:", host: "www.elearningfreak.com", referrer: "https://www.elearningfreak.com/"

Any ideas on how to prevent the site from hitting a 500 error in this case?

It looks like my site has hit this error multiple times in the past 2 weeks

I noticed a difference between the version of maxmind reader.php mentioned here:

maxmind/MaxMind-DB-Reader-php@f7ac2fc