ご連絡（ごれんらく） means polite contact / communication. It is very common in business emails, customer service, and formal messages.
The prefix ご works differently depending on who is doing the contacting.
When you contact someone, ご連絡します（ごれんらくします） sounds humble. You are politely lowering yourself when speaking to a client, boss, or someone outside your group.
When they contact you, as in ご連絡ありがとうございます（ごれんらくありがとうございます）, ご shows respect toward the other person’s action.
Plain 連絡（れんらく） is fine with friends, family, and close coworkers. But with clients, superiors, or in professional email, ご連絡 is the safer, more polished choice.