Fatal Error with Constant Contact plugin

There seems to be a conflict between BackWPup and the Constant Contact plugin. Hoping you might have a resolution. When I activate the Constant Contact plugin, I get this fatal error message:

Fatal error: Uncaught TypeError: Argument 3 passed to GuzzleHttp\Client::request() must be of the type array, string given, called in /home/mhcboss/public_html/wp-content/plugins/backwpup/vendor/guzzlehttp/guzzle/src/Client.php on line 89 and defined in /home/mhcboss/public_html/wp-content/plugins/backwpup/vendor/guzzlehttp/guzzle/src/Client.php:128 Stack trace: #0 /home/mhcboss/public_html/wp-content/plugins/backwpup/vendor/guzzlehttp/guzzle/src/Client.php(89): GuzzleHttp\Client->request(‘createRequest’, ‘GET’, ‘https://api.con…’) #1 /home/mhcboss/public_html/wp-content/plugins/constant-contact-forms/vendor/constantcontact/constantcontact/src/Ctct/Services/BaseService.php(65): GuzzleHttp\Client->__call(‘createRequest’, Array) #2 /home/mhcboss/public_html/wp-content/plugins/constant-contact-forms/vendor/constantcontact/constantcontact/src/Ctct/Services/ListService.php(31): Ctct\Services\BaseService->createBaseRequest(‘7b906d68-b6da-4…’, ‘GET’, ‘https://api.con…’) #3 /home/mhcboss/public_html/wp-content/plugins/const in /home/mhcboss/public_html/wp-content/plugins/backwpup/vendor/guzzlehttp/guzzle/src/Client.php on line 128

Here is my system info:
WordPress version 5.5
BackWPup version 3.7.1 Get pro.
PHP version 7.4.8 (64bit)
MySQL version 10.3.23-MariaDB-log-cll-lve
cURL version 7.62.0
cURL SSL version OpenSSL/1.0.2k
WP-Cron url https://dev1.mountainhomecenter.com/wp-cron.php
Server self connect Response Test O.K.
Document root /home/mhcboss/public_html
Temp folder /home/mhcboss/public_html/wp-content/uploads/backwpup-2b05fd-temp/
Log folder /home/mhcboss/public_html/wp-content/uploads/backwpup-2b05fd-logs/
Server LiteSpeed
Operating System Linux
PHP SAPI litespeed
Current PHP user mhcboss
Maximum execution time 30 seconds
BackWPup maximum script execution time 30 seconds
Alternative WP Cron Off
Disabled WP Cron Off
CHMOD Dir 493
Server Time 19:27
Blog Time 12:27
Blog Timezone America/Los_Angeles
Blog Time offset -7 hours
Blog language en-US
MySQL Client encoding utf8mb4
PHP Memory limit 256M
WP memory limit 40M
WP maximum memory limit 256M
Memory in use 65.00 MB
Loaded PHP Extensions: Core, PDO, PDO_ODBC, Phar, Reflection, SPL, SimpleXML, bcmath, bz2, calendar, ctype, curl, date, dba, dom, enchant, exif, fileinfo, filter, ftp, gd, gettext, gmp, hash, i360, iconv, imap, intl, json, ldap, libxml, litespeed, mbstring, mysqli, mysqlnd, odbc, openssl, pcntl, pcre, pdo_mysql, pdo_sqlite, posix, pspell, readline, session, shmop, snmp, soap, sockets, sqlite3, standard, sysvmsg, sysvsem, sysvshm, timezonedb, tokenizer, xml, xmlreader, xmlrpc, xmlwriter, xsl, zip, zlib