i have mikrotik 750r2, i have blocked all the internet traffic only alloed smtp and pop.i have 230 users who pop the emails from my hosting site. i am facing a problem that in the morning when all users send and receive the email, outlook/thunderbird on all 230 email clients gives error that smtp authentication failed unable to send the email and gives a popup window to give the new password and i retry the password and some time it accept some time it gives the error again. then 2-3 hours it works fine the after 2-3 hours it gives same error again. my confifuration is follows plese guide me to solve this issue
/ip firewall nat
add action=masquerade chain=srcnat comment=“default configuration” out-interface=Public
add chain=forward dst-port=995 protocol=tcp src-address=192.168.25.0/24
add chain=forward dst-address=192.168.25.0/24 protocol=tcp src-port=995
add chain=forward dst-port=587 protocol=tcp src-address=192.168.25.0/24
add chain=forward dst-address=192.168.25.0/24 protocol=tcp src-port=58
add action=drop chain=forward