sendmail with esp32 + w5500

as my esp32 device is located in a place where there is no reliable wifi, i would like to use wired lan to send status emails. therefore i attached a w5500 shield. wiring is ok as with the same hardware, i am able to run a chatserver on the device. i use the ethernet3 library for the w5500 and now i added the emailsender library. i tried to use the code according to some examples i found in the net, but it looks like i don't get any packets out of the w5500. at least my router reports no data at all coming from  the ip of the device. i would like to send with smtp, using either a gmail or gmx account. i tried both smtp server configurations but always get the status information: 0 2 Could not connect to mail server but i don't think that my device even tries to connect to an smtp server as i register no packets coming from it. is there a setup example for using with the w5500 somewhere? i tried for hours but have no more ideas how to go on... ;-(