Plugin Stopped Working

I have this plugin installed on 2 sites, and it has stopped working on both of them.

On my development server, I was able to install the prior version (3.1.5) and get the plugin working again. Unfortunately, on the live server, even 3.1.5 does not work.

When I try to authorize with the plugin, I am able to login to the Constant Contact account and click the authorize button. I am then returned to the WordPress admin, and the main content pane is blank. If I re-click on the link to the Constant Contact settings, the screen stays blank. I have to deactivate the plugin and reactivate it to be able to try to authorize again.

My error log shows the following:

Mar 26, 20:05:49 PHP Warning: Illegal offset type in /wp-includes/class-wp-error.php on line 243
Mar 26, 20:05:49 PHP Warning: array_key_exists() expects parameter 2 to be array, null given in /wp-content/plugins/constant-contact-api/vendor/constantcontact/constantcontact/src/Ctct/Auth/CtctOAuth2.php on line 74
Mar 26, 20:05:50 PHP Warning: Invalid argument supplied for foreach() in /wp-content/plugins/constant-contact-api/vendor/constantcontact/constantcontact/src/Ctct/Services/ListService.php on line 30
Mar 26, 20:05:50 PHP Warning: Invalid argument supplied for foreach() in /wp-content/plugins/constant-contact-api/vendor/constantcontact/constantcontact/src/Ctct/Services/ListService.php on line 30
Mar 26, 20:05:50 PHP Warning: Invalid argument supplied for foreach() in /wp-content/plugins/constant-contact-api/vendor/constantcontact/constantcontact/src/Ctct/Services/ListService.php on line 30
Mar 26, 20:05:50 PHP Warning: Invalid argument supplied for foreach() in /wp-content/plugins/constant-contact-api/vendor/constantcontact/constantcontact/src/Ctct/Services/ListService.php on line 30
Mar 26, 20:05:50 PHP Warning: trim() expects parameter 1 to be string, object given in /wp-includes/formatting.php on line 376
Mar 26, 20:05:50 PHP Catchable fatal error: Object of class WP_Error could not be converted to string in /wp-includes/formatting.php on line 379

Any ideas for a fix, or a workaround?

Thanks,

Barry

https://ww.wp.xz.cn/plugins/constant-contact-api/