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email error

“Destination smtp server rejected the sender” – Here’s how to fix it

Email errors are quite frustrating especially when you do not know why it is happening!

Though the bounce mail show some error text, that will just serve as a pointer to the possible reasons for the error.

One such error is “Destination smtp server rejected the sender” shown in email marketing programs like SendBlaster.

At Bobcares, we resolve many email related errors as part of our Outsourced Technical Support services for Web hosts.

Today, we’ll see the top reasons for this error and how we fix it.



wp_mail() function not working? Here’s how to fix it

WordPress website owners prefer the built-in “wp_mail() function, because they can send emails easily.

But, sometimes wp_mail() function doesn’t work properly due to server security restrictions, IP blacklists, etc.

My wp_mail() function not works” is a common problem raised by WordPress owners.

At Bobcares, we resolve such WordPress errors as part of our Outsourced Technical Support for web hosting providers.


How to fix “smtp error: could not authenticate” in PHPMailer

PHPMailer is a great tool to send emails safely and easily using SMTP authentication.

But, sometimes this may fail due to incompatible server settings or incorrect SMTP configuration.

smtp error: could not authenticate” is one such problem reported by website owners when using PHPmailer to send emails.

At Bobcares, we resolve such email errors as part of our Outsourced Technical Support for web hosting providers.


How to fix “SMTP Error: Could not connect to SMTP host.”

Emails play a crucial role in online businesses. It can be bothersome when emails stop working. You may lose an urgent invite or important notification.

As part of our Dedicated Support Services, we help website owners configure email services for their businesses and assist server owners to fix email errors.

One such commonly encountered error is “SMTP Error: Could not connect to SMTP host.” Today we’ll see what causes that error and how we fix it.


“My IP is blacklisted. How to remove it?” – Experts answer

Help! My IP is blacklisted. All my mails are bouncing. How to remove it?

This is a common support request we resolve here at our Server Administration Services support desk.

Website owners wake up one day to find all their business mails bouncing, citing the reason that the server is a source of spam. (more…)

How to fix “550-previous (cached) callout verification failure” email error

Spammers have made life difficult for us all.

These days even legitimate mails get snagged in the vast array of anti-spam defenses deployed by companies.

One such commonly misclassified anti-spam bounce is:
SMTP error from remote mail server after RCPT TO:<>:
host [x.x.x.x]: 550-Verification failed for <>
550-Previous (cached) callout verification failure
550 Sender verify failed


PHP mail function not working in cPanel – Causes and Fixes

PHP applications like WordPress, Joomla etc. send mail using a PHP feature (aka function) called “mail()”.

Hackers largely exploit the PHP mail function for spamming.

No wonder, Webhosting companies disable PHP mail function on the server as a rule of thumb.

This causes mail from applications like wordpress to fail with the following error.


2 causes for “550 REJECTED – Bad HELO – Host impersonating [DOMAIN]” & how to fix it

Mail errors. They hit you at your most vulnerable, and make you want to smash your laptop.

We know. Because we help website owners resolve email errors and other technical issues as part of our Outsourced Hosting Support services for web hosting providers.

Hosting users frustrated with cryptic email errors would submit a support request, and we’ll fix it for them in a few minutes.

Here’s an email bounce error we fixed recently in a Linux cPanel/WHM server: (more…)

How to fix “554 Too many recipients” email error

Here at, we provide Outsourced Tech Support to web hosting providers. As part of our service, we resolve email errors posted by hosting users.

A common email bounce error we see in VPS and Shared servers is:

The rejected e-mail address was ''. Subject 'My mail subject', Server Error: 554, Server Response: 554 Too many recipients, Server: '', Windows Live Mail Error ID: 0x800CCC79, Protocol: SMTP, Port: 587, Secure(SSL): No

This error is seen when people attempt to send group mails with a large CC or BCC list. (more…)