bitmask app prevents sending e-mails
in my lineageos-device i use the bitmask app as my vpn-tool. for sending e-mails i use the app k-9 mail. it works really fine with one exception:
bitmask prevents k-9 mail sending e-mails with my posteo-account. posteo is an german mail-provider which is focused on security and privacy. everytime i try to send an e-mail from my posreo-account, it says:
Mails could not be sent (my translation from the german notice). SocketTimeoutExeption: failed to connect to posteo.de/2a..
receiving mails is no problem.
with my other account (not posteo) it works without any problems.
after several mails with the posteo-support they advised me to ask here in the forum if the bitmask app blocks the relevant ports:
ssl/tls, port 465 or starttls, port 587
it does not matter which port i try, the note is allways:
Could not finish installation. Can not connect with the server. (Unable to open connection to SMTP server.)
on my desktop computer i have no problems at all with a similar combination: bitmask, thunderbird, posteo. sending and receiving were and are never a problem.