I am having the exact same problem
Not expected HTTP response:Status-Code: 429
Server: openresty
Date: Wed, 22 Apr 2020 18:51:34 GMT
Content-length: 0
Accept-ranges: bytes
Age: 0
Vary: User-Agent
X-cache: uncached
X-cache-hit: MISS
X-backend: all_requests
Strict-transport-security: max-age=31536000; includeSubDomains
DEBUG INFO
WordPress version: 5.4
BackWPup version: 3.7.1
PHP version: 7.3.12 (64bit)
MySQL version: 5.7.26-29-log
cURL version: 7.45.0
cURL SSL version: OpenSSL/1.0.1e
WP-Cron url: https://vimby.com/wp-cron.php
Server self connect: Not expected HTTP response:
Status-Code: 429
Server: openresty
Date: Wed, 22 Apr 2020 18:51:34 GMT
Content-length: 0
Accept-ranges: bytes
Age: 0
Vary: User-Agent
X-cache: uncached
X-cache-hit: MISS
X-backend: all_requests
Strict-transport-security: max-age=31536000; includeSubDomains
Document root: /var/www
Temp folder: /var/www/wp-content/uploads/backwpup-350783-temp/
Log folder: /var/www/wp-content/uploads/backwpup-350783-logs/
Server: Apache
Operating System: Linux
PHP SAPI: cgi-fcgi
Current PHP user: root
Maximum execution time: 300 seconds
BackWPup maximum script execution time: 30 seconds
Alternative WP Cron: Off
Disabled WP Cron: Off
CHMOD Dir: 453
Server Time: 18:51
Blog Time: 18:51
Blog Timezone:
Blog Time offset: 0 hours
Blog language: en-US
MySQL Client encoding: utf8mb4
PHP Memory limit: 256M
WP memory limit: 128M
WP maximum memory limit: 256M
Memory in use: 2.00 MB
Loaded PHP Extensions:: Core, PDO, Phar, Reflection, SPL, SimpleXML, Zend OPcache, apc, apcu, bcmath, bz2, calendar, cgi-fcgi, ctype, curl, date, dba, dom, exif, fileinfo, filter, ftp, gd, gettext, hash, iconv, igbinary, imagick, json, libxml, mbstring, mcrypt, memcache, mysql, mysqli, mysqlnd, openssl, pcntl, pcre, pdo_mysql, pdo_sqlite, posix, pspell, readline, session, shmop, soap, sockets, sqlite3, standard, sysvmsg, sysvsem, sysvshm, tokenizer, wddx, xml, xmlreader, xmlrpc, xmlwriter, xsl, yaml, zip, zlib