Moved to new server, IPN validation errors - can't solve

We moved to a new server last week (old server ran Plesk, new server runs cPanel) and ever since then, our aMember 3.1.8 Pro has been giving us errors and not handling transactions properly. It seems to affect about one-fourth of all transactions, but we cannot decipher a pattern of why transactions result in and others don't.

We believe the main issue is with IPN validation. Our server seems to not be able to communicate with Pay Pal. But for a week we've had smart people at the hosting company, our migration company, Pay Pal, and a couple short exchanges with aMember's tech team and we cannot figure out what's happening.

In aMember's ERROR/DEBUG LOG is when it tries to DEBUG a transaction with Pay Pal, around 25 percent of the time the DEBUG doesn't resolve in the next entry, but instead includes an ERROR line. For instance, this morning since that change was made, we see this entry in the ERROR/DEBUG LOG in aMember dated 2/26/2013 at 10:21... There are four entries within one second.

First (working from bottom to top, or low to high) is a block of text saying "paypal_R DEBUG" with a bunch of details.

Then two smaller blocks of text that give a "WARNING." One talks about "fsockopen" and "php_network_getaddress failed" with the mention of line 313, then another "WARNING" that says "unable to connect to www.paypal.com."

Then the fourth block of text related to that transaction is the message "paypal_r ERROR" statwing it cannot validate Pay Pal IPN post because the name or service not known.

I would have thought the hosting company would have been able to see this pattern and change something in our settings so the server could basically ping back info to Pay Pal successfully to complete transactions, but multiple people haven't been able to figure it out. They're also not aMember experts, but I would have thought by now someone would have had an ah-ha moment and figured out what's up.

Does anyone here have any ideas? Again, aMember worked fine until thes server migration. Then it's consistently delivered errors where, for instance, someone cancels a sub but aMember still shows them as current even though if we log into Pay Pal they clearly show they canceled. Or a new subscriber will have their payment go through, but aMember has them showing as still PENDING. Or a recurring payment takes place, but it doesn't show up as having occured when we look that person's subscription up.

I'm assuming nothing - this might be an issue with aMember or an issue with our server settings (I lean that way).

Might help if you include this 'bunch of details' since they relate to the error message and could hold the clues.

Plus you give no details about the difference in the two servers.

Sure thing. I was trying to just convey key details, but here's the full blocks of error messages.

===

Here's the first entry:

paypal_r DEBUG: ​

transaction_subject => (edited off aMember help board post for privacy reasons)​

payment_date => 05:28:21 Feb 17, 2013 PST​

txn_type => subscr_payment​

subscr_id => S-6PD16------------​

(edited off aMember help board post for privacy reasons)​

last_name => Fanjoy​

residence_country => CA​

item_name => ​

(edited off aMember help board post for privacy reasons)​

payment_gross => 27.95​

mc_currency => USD​

business => ​

(edited off aMember help board post for privacy reasons)​

payment_type => echeck​

protection_eligibility => Ineligible​

verify_sign => ​

(edited off aMember help board post for privacy reasons)​

payer_status => verified​

payer_email => ​

(edited off aMember help board post for privacy reasons)​

txn_id => ​

(edited off aMember help board post for privacy reasons)​

receiver_email => ​

(edited off aMember help board post for privacy reasons)​

first_name => James​

payer_id => ​

(edited off aMember help board post for privacy reasons)​

receiver_id => ​

(edited off aMember help board post for privacy reasons)​

echeck_time_processed => 07:21:33 Feb 26, 2013 PST​

recur_times => 4147316885​

payment_status => Completed​

payment_fee => 1.39​

mc_fee => 1.39​

mc_gross => 27.95​

charset => windows-1252​

notify_version => 3.7​

ipn_track_id => 2​

(edited off aMember help board post for privacy reasons)​

Then here's the second entry above it​

<b>WARNING:</b> fsockopen() [<a href='function.fsockopen'>function.fsockopen</a>]: php_network_getaddresses: getaddrinfo failed: Name or service not known in line 313 of file /home/(removed by me)/public_html/amember/plugins/payment/paypal_r/paypal_r.inc.php​

Then here's the third entry above that...​

<b>WARNING:</b> fsockopen() [<a href='function.fsockopen'>function.fsockopen</a>]: unable to connect to www.paypal.com:80 (php_network_getaddresses: getaddrinfo failed: Name or service not known) in line 313 of file /home/(removed by me)/public_html/amember/plugins/payment/paypal_r/paypal_r.inc.php​

Then here's the fourth and final entry marked ERROR (I have edited out all of the same info that was repeated in the first entry above)​

paypal_r ERROR: IPN validation error: Cannot validate PayPal IPN post: FOPEN [www.paypal.com] results to [php_network_getaddresses: getaddrinfo failed: Name or service not known (0)]​

THEORY:

Could this be related to updating to a newer PHP and MySQL on my new server? My old server was running Plesk 8 with older PHP 5.1.0 and mySQL 5.0.0.

It now says this on my aMember home page...

aMember 3.1.8PRO
PHP 5.3.19 (cgi-fcgi)
OS Linux server.
MySQL 5.1.68-cll

===

I looked up aMember Requirements.......

PHP version: 5.x (Required from aMember PRO 3.2.x);
MySQL version 3.23 or newer;
Apache WebServer (it's usually only installed on Unix/Linux hosting servers, and almost never on Windows);
For aMember Trial only - ability to run IonCube Loader or Zend Optimizer is required. aMember PRO no longer has Zend or IonCube encrypted files.
If you are unsure whether your hosting meets these requirements, please contact your host company for confirmation.
We have also released a tester script to check your webhost's compatibility.

You might need to upgrade to latest version 3 of aMember.