Constant Contact api Plugin for WordPress Fetal Error

[Axis]

Dear Team,

We are having fetal error after upgrading Wordpress 5.8. We are using both plugins Constant Contact Plugin for WordPress & Constant Contact Forms for WordPress so the issue is with Constant Contact Plugin for WordPress.

Please see the below error and please try to share us the best solution as we need both of these plugins.

[30-Jul-2021 13:07:34 UTC] PHP Fatal error:  Uncaught TypeError: Argument 1 passed to GuzzleHttp\Client::send() must implement interface Psr\Http\Message\RequestInterface, instance of GuzzleHttp\Psr7\Response given, called in /home/omuhra/public_html/strategicaxis.ae/wp-content/plugins/constant-contact-api/vendor/constantcontact/constantcontact/src/Ctct/Services/AccountService.php on line 83 and defined in /home/omuhra/public_html/strategicaxis.ae/wp-content/plugins/constant-contact-api/vendor/guzzlehttp/guzzle/src/Client.php:101
Stack trace:
#0 /home/omuhra/public_html/strategicaxis.ae/wp-content/plugins/constant-contact-api/vendor/constantcontact/constantcontact/src/Ctct/Services/AccountService.php(83): GuzzleHttp\Client->send(Object(GuzzleHttp\Psr7\Response))
#1 /home/omuhra/public_html/strategicaxis.ae/wp-content/plugins/constant-contact-forms/includes/class-api.php(124): Ctct\Services\AccountService->getAccountInfo('02bbf862-4995-4...')
#2 /home/omuhra/public_html/strategicaxis.ae/wp-content/plugins/constant-contact-forms/includes/class-api.php(981 in /home/omuhra/public_html/strategicaxis.ae/wp-content/plugins/constant-contact-api/vendor/guzzlehttp/guzzle/src/Client.php on line 101

[Courtney_E]

Thank you for reaching out to Constant Contact API Developer Support. My team is here to assist outside software developers with questions about building into Constant Contact's API.

While Constant Contact Forms was created and is supported by Constant Contact, it looks like Constant Contact for WordPress was created and is supported by the third party developer Katz Web Services, Inc. and also has not been tested past WordPress version 4.6.21, so it may no longer be maintained or supported and may have compatibility issues when used with more recent versions of WordPress.

Constant Contact Forms - By Constant Contact
WordPress Version:5.2.0 or higher
Tested up to: 5.8.0
https://wordpress.org/plugins/constant-contact-forms/

Constant Contact for WordPress - By Katz Web Services, Inc.
WordPress Version:3.3 or higher
Tested up to: 4.6.21
https://wordpress.org/plugins/constant-contact-api/

For assistance with the third party integration Constant Contact for WordPress developed by Katz Web Services, Inc., you can contact the plugin’s developer via the WordPress support forums:

Constant Contact for WordPress Support Forum
https://wordpress.org/support/plugin/constant-contact-api/

Please have a look and let us know if you have any other questions!