"Unable to connect to the server"

"Unable to connect to the server"

Hi,

I'm trying to make a migration.

Under migration > Server Details I have entered: IMAP, Server type Other, Security None and in Server name: 148.251.128.149 or srv.ithemis.gr or www.ithemis.gr. It returns "Successfully saved!" for all the above server names. By the way, when i'm trying to enter ithemis.gr it returns "Enter a valid Server Name".
After that, when I' trying to add account [the account already created under ZOHO] using: Source User Name <account name>, Source Password <the password of source account>, Destination Email Address <the same as "account name"> and priority 1, it returns "Unable to connect to the server". I had also tried with SSL option under Server details [it returns "Successfully saved!"] but to no avail when it comes to add an account.

Is it possible to investigate the above issue or provide me pointers of how to solve it?

Regards