They flirted then went quiet? What to send next

Start with her last message, not the silence. If it was a tease with a hook in it, she was inviting you to keep playing, and a quiet stretch usually means the invitation got buried under a busy day. If it was a joke with nothing for you to grab onto, she may have simply run out of material.

Then check the gap. A few hours means nothing. Two or three days after a fast, warm exchange usually means she meant to answer and never came back to it. A week or more of nothing tends to mean the thread has cooled on her side, even if it felt warm to you.

Your reply has to do three jobs. The first is to pick up her last line instead of starting a new topic. That tells her the thread is still open and that she doesn't have to re-read the whole conversation to catch up.

The second job is to make answering cheap. Ask something she can respond to in a few words, like a choice between two options or a plan with a clear day and time. Open questions about her week ask for effort after a silence, so skip them.

The third job is to leave the gap alone. Don't ask why she went quiet, don't mention how long it's been, and don't joke about being ignored. Any of those forces her to explain herself, and someone who has to explain is already halfway out the door.

Give a first reply after a silence about a day before you send anything else, unless she's already answered. Sending twice in a few hours reads as anxious and gives her a reason to ignore both. If your first message landed and she replied, match the pace she sets, roughly keeping pace with how long she takes between messages.

If nothing comes back, send one follow-up after three to four days, and make it lighter than the first, something that gives her an easy out without guilt. Don't send a third message in the same week. If two messages across about two weeks get no answer, stop. Silence after two tries is her answer, and the cleanest exit is to let the thread end without a comment.