Did you check your Journal to see if the Writ is in fact finished? Did you wait long enough at the crafting table to see the "Completed" message show up?

Here are some tips:

First, only make Glyphs with Ta's, other Aspects will not be accepted.

Second, in the earlier levels, there are two potency runes, the writs typically ask for the lower of the two to be made into Glyphs, the higher level one is turned in for Writs from time to time. But the UI will show you the name of the Glyph being made, so you can make sure it is right before hitting R.

Third, are you trying to drop them off at the correct location? You can only drop off in zones in your home alliance for the level of the writ your working on. It will glitch sometimes and let you drop off in the zone you are in, but that is a glitch, not normal.