Issues after upgrade

Hi,

My client (canultra.ca) is running the latest version of membership pro version 4.3.1 and Joomla version 5.4.0.
They are using the PayPal plugin V1 to process payments.
The server has been running for a few years with no issues.
After the last upgrade all the successful PayPal payments are marked as Pending and no emails are sent to the Admins.
When the transaction is manually marked as Approved a single Approved email is sent to the member, but no emails are sent to the Admins.

I have checked the settings for account creation and paypal and I cannot find any reason for this.

Please could you suggest a fix for for the issue and how to debug it 

Thanks.

Hello

Usually, it causes by PayPal IPN Message could not reach your site to inform Membership Pro about the payment for some reasons. For this, please submit a support ticket and I will guide you for next step

BTW, latest version of the extension is 4.4.0

Regards,

Tuan