The basic parameters of the service are as follows:
the default (standard) size of an employee's mailbox is 4 GB,
the default (standard) size of a student's mailbox in the Microsoft 365 service is 50 GB,
the maximum size of a single email message (the content of the email including attachments), intended for sending, is 20 MB. Remember that the size of each e-mail consists of its content and attachments. Thus, the longer the e-mail content, the correspondingly smaller will be the maximum size of the attachment that can be sent with the message. If you want to send a much larger attachment, use the Drive service within Webmail.
the older Roundcube webmail client has a built-in limitation on the size of a single attachment to 14 MB. This limitation is not present in other tools, such as the Mozilla Thunderbird client or the Webmail application.
a single e-mail message can be addressed to a maximum of 50 recipients.
Dear users! Remember that mail administrators, as well as other employees of the IT Services Centre (CUI), NEVER ask you to send/provide your LOGIN along with your mail PASSWORD at the same time (or the PASSWORD alone) for any purpose (e.g. to confirm the validity of your account, to retrieve your data, to confirm your identity, to enlarge your mailbox, or to unlock your mailbox etc.). Do not disclose your account password to any person!