Warnings Redirection for Contact Form 7 plugin

Hello,

I get those 2 warnings on site (but not on others) ???
Any clue on why this ?

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<b>Warning</b>:  Declaration of Ext_Accessibe::get($key) should be compatible with WPCF7R_Action::get($key, $default = '') in <b>/var/www/clients/client2/web3/web/exper2eftn5/wp-content/plugins/wpcf7-redirect/classes/aff/class-ext-accessibe.php</b> on line <b>213</b><br />
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<b>Warning</b>:  Use of undefined constant ACCESSIBE_API_URI - assumed 'ACCESSIBE_API_URI' (this will throw an Error in a future version of PHP) in <b>/var/www/clients/client2/web3/web/exper2eftn5/wp-content/plugins/wpcf7-redirect/classes/aff/class-ext-accessibe.php</b> on line <b>618</b><br />
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