das war die Lösung habe eine neue SubDomain eingerichtet und nicht den localhost als DB genommen sondern den mysql Namen
danach hat es sofort funktioniert

DANKE

ja unter einer Wordpress Seite

Das ist die Info von PHP

mysqli
MysqlI Support    enabled
Client API library version    mysqlnd 5.0.12-dev - 20150407 - $Id: 7cc7cc96e675f6d72e5cf0f267f48e167c2abb23 $
Active Persistent Links    0
Inactive Persistent Links    0
Active Links    0
Directive    Local Value    Master Value
mysqli.allow_local_infile    Off    Off
mysqli.allow_persistent    On    On
mysqli.default_host    no value    no value
mysqli.default_port    3306    3306
mysqli.default_pw    no value    no value
mysqli.default_socket    no value    no value
mysqli.default_user    no value    no value
mysqli.max_links    Unlimited    Unlimited
mysqli.max_persistent    Unlimited    Unlimited
mysqli.reconnect    Off    Off
mysqli.rollback_on_cached_plink    Off    Off

Steffen schrieb:

Eigener Server ? Ist halt ein Webhosting Paket in dem ich 5 Domains verwalte, in dem Paket ist ein Webspace enthalten.
PHP-Einstellung:
7-73 LATEST-STANDARD
PHP 7
[PHP]
  engine = On
  short_open_tag = On
  date.timezone = "Europe/Berlin"
  precision = 14
  y2k_compliance = Off
  output_buffering = Off
  output_handler =
  unserialize_callback_func =
  zlib.output_compression =
  implicit_flush = Off
  allow_call_time_pass_reference = On
  safe_mode = Off
  safe_mode_gid =
  safe_mode_include_dir =
  safe_mode_exec_dir =
  safe_mode_allowed_env_vars = "PHP_"
  safe_mode_protected_env_vars = "LD_LIBRARY_PATH"
  disable_functions =
  highlight.string = "#CC0000"
  highlight.comment = "#FF9900"
  highlight.keyword = "#006600"
  highlight.bg = "#FFFFFF"
  highlight.default = "#0000CC"
  highlight.html = "#000000"
  expose_php = 1
  max_execution_time = 300
  memory_limit = 100M
  error_reporting = 32759
  display_startup_errors =
  track_errors = Off
  variables_order = "EGPCS"
  register_argc_argv = On
  post_max_size = 8M
  gpc_order = "GPC"
  magic_quotes_runtime = Off
  magic_quotes_sybase = Off
  default_mimetype = "text/html"
  doc_root =
  user_dir =
  enable_dl = On
  file_uploads = 1
  allow_url_include = 0
  asp_tags = On
  allow_url_fopen = Off
  display_errors = On
  log_errors = Off
  error_log =
  register_globals = Off
  magic_quotes_gpc = On
  auto_prepend_file =
  auto_append_file =
  include_path = ".:/usr/local/lib/php"
  upload_max_filesize = 8M
  extension_dir = "./"
  zend_optimizer.enable_loader = Off
  zend_optimizer.optimization_level =

[mail function]
  SMTP = "localhost"
  sendmail_from = "me@localhost.com"

[SQL]
  sql.safe_mode = Off

[ODBC]
  odbc.allow_persistent = 1
  odbc.check_persistent = 1
  odbc.max_persistent = -1
  odbc.max_links = -1
  odbc.defaultlrl = 4096
  odbc.defaultbinmode = 1

[MySQL]
  mysql.allow_persistent = Off
  mysql.max_persistent = -1
  mysql.max_links = -1
  mysql.default_port =
  mysql.default_socket =
  mysql.default_host =
  mysql.default_user =
  mysql.default_password =

[PostgresSQL]
  pgsql.allow_persistent = On
  pgsql.auto_reset_persistent =
  pgsql.max_persistent = -1
  pgsql.max_links = -1

[bcmath]
  bcmath.scale = 0

[Session]
  session.serialize_handler = "php"
  session.gc_probability = 1
  session.referer_check =
  session.entropy_length = 0
  session.entropy_file =
  session.cache_limiter = "nocache"
  session.cache_expire = 180
  session.use_trans_sid = 1
  url_rewriter.tags = "a=href,area=href,frame=src,input=src,form=fakeentry"
  session.save_handler = "files"
  session.save_path = "/tmp"
  session.use_cookies = On
  session.name = "PHPSESSID"
  session.auto_start = Off
  session.cookie_lifetime = 0
  session.cookie_path = "/"
  session.cookie_domain =
  session.gc_maxlifetime = 1440

... leider kommt der Fehler immer noch

Bin da leider völlig unerfahren daher benötige ich Hilfe hierbei- DANKE

Eigener Server? Es fehlt wie es aussieht die PHP Erweiterung für mysql. das Modul heisst mysqli.
Welche PHP Version wird denn eingesetzt?