doesn't send e mail bigger than 1 mb

Hi since some weeks, when I send email more than 1mb dimension,  em send it many times but it appears as it didn’t send it and the and says that the connection is failed how can I solve it?    thanks!                   

What server are you using? Can you check you have the correct settings for SMTP.

server aruba,  SMPT port 587, pop3 110

Can you try SMTP port 465, security policy Use SSL/TLS on special port (legacy). See if that makes a difference