fwrite(): send of 6 bytes failed with errno=32 Broken pipe Laravel and Mailtrap

I am using laravel and Mailtrap for testing emails. Everything was working fine until only recently the app give the error below upon trying to send a mail

 ErrorException (E_NOTICE)
fwrite(): send of 6 bytes failed with errno=32 Broken pipe
Previous exceptions

    Expected response code 250 but got an empty response (0)

My last successful email was 8 days ago (19th Feb 2020). I have not made any change to my .env during this time so I don't understand why it is not working. I have tried port 25, 587 and 2525 with no success. Below is my .env entry

QUEUE_CONNECTION=sync

MAIL_DRIVER=smtp
MAIL_HOST=smtp.mailtrap.io
MAIL_PORT=2525
MAIL_USERNAME=blahblah
MAIL_PASSWORD=blahblah
MAIL_ENCRYPTION=null

MAIL_FROM_ADDRESS=subscription@blah.com
MAIL_FROM_NAME='Subscription'

MAIL_REPLY_TO_ADDRESS=noreply@blah.com
MAIL_REPLY_TO_NAME='Subscription'

Please any ideas how to solve this issue?

via Chebli Mohamed