Translation:Please keep in touch.
I had the same question until I looked up 联系 on Yellowbridge and saw that it means "get in touch" or "contact." There is no meaning of "keep" or "stay" in this word. The definition for 保持 is "keep/maintain/preserve."
So together it means "maintain contact", "keep getting in touch", or "keep/stay in touch/contact."
This service desperately needs to ensure students have learnt individual words rather than sling a sentence at them and expect a four character string to be known; and relying on hover translations and available tiles to allow the student to get it right. It just doesn't help learning at all, as one isn't going to recall a four character string simply because it comes up "once in a blue moon". This strategy is deeply flawed. (They have a comparable flaw when they want students to listen to and repeat long sentences too. There needs to be understanding and correct pronunciation of the individual words first not desperate attempts to recall and repeat a long sentence that was heard a few moments earlier.)