Use HTTPS with some phones
From Memotoo Wiki
Using https://... rather than http://... is a better level of security: regardless of the network used (Wi-Fi, GPRS, 3G ...), the informations exchanged with the server (IDs, passwords, data ...) are not transmitted in clear.
To use HTTPS with your phone, may be you must install the root certificate in your mobile that it could communicate with Memotoo because it is not present by default.
So download the two certificate files:
https://www.geotrust.com/resources/root_certificates/certificates/Equifax_Secure_eBusiness_CA-1_DER.cer
https://www.geotrust.com/resources/root_certificates/certificates/Equifax_Secure_Certificate_Authority_DER.cer
Install it by opening the files on your mobile.
Now change the address with the HTTPS url for the synchronization with Memotoo:
https://sync.memotoo.com/syncml