Unicom reminded me that I received the multimedia message of 86 13979986670. Please log in to mmbox.myuni.com for details. How can I check it?

Dear, if the receiver's mobile phone can't receive MMS within 2 hours due to reasons such as power off, being out of service area, being on a call, etc. , the MMS will be transferred to the MMS network mailbox of the receiver's mobile phone (that is, MMS album/), and the MMS platform will still keep the MMS and continue to try to send it to the receiver's mobile phone. Once the receiver's mobile phone has the reception conditions, it will still receive MMS. However, if the recipient's mobile phone still doesn't receive the multimedia message within 48 hours, the system will delete the multimedia message and you can't receive it through your mobile phone. You can only log in to the multimedia message network mailbox through the URL address, user name and password sent by the mail arrival notification and extract the multimedia message. The user name is your mobile phone number. If you don't know the password, you can click Forgot Password to get it.