Paypal failed to send ipn's

Good Morning,
since a few days ago I have received emails from paypal with the following information:
(automatically translated from Portuguese to English)
"Dear DIOGO RAMOS,

See the server that controls PayPal instant payment (IPN) notifications. Failed to send IPNs to the following URL (s):
http://www.("mydomain.com")/index.php?option=com_osmembership&task=payment_confirm&payment_method=os_paypal
If you do not recognize this URL, you may be using a service provider that is using IPN on your behalf. Contact your service provider with the above information. If this issue continues, IPNs can be disabled from your account.

Thank you for your prompt attention to this issue.

Carefully,
PayPal"


This only happens with osMembershipPro links.
how to solve the problem?
Thank you

Hi Diogo

Might happen because you are using a very old version of Membership Pro and then you updated your server to PHP 7.0 and it is not compatible?

I checked your account but could not see Membership Pro, so I could not guess the version of Membership Pro you are using

Regards,

Tuan

Hi Tuan!

I'm using Membership Pro version 1.6.7
I bought it in 2014/2015, i can't precise it exactly.

However i havn't made any recent changes on my server...

Thanks

Hi Diogo

That's a very old version of Membership Pro, so I think it might be incompatible with Joomla version you are using. What's the version of Joomla you are using? If you are using latest version 3.8.x, you should purchase and update your site to latest version of Membership Pro

Also, do you know what PHP version running on your server? If it is PHP 7, then that old version won't work

Also, check and make sure the os_paypal payment plugin has Access set to Public, instead of Registered, too

Tuan