Issue with setting AC

Character Sheet is the "D&D 5E by Roll20" I am the GM. My paladin player is wearing Chain Mail.  Base AC: 16 He sometimes carries a Shield.  +2 AC (when I click it to be equipped) He took the Fighting Style: Defense.  +1 AC (when wearing armor) The problem is that the AC calculation is almost always wrong.  Sometimes it was showing 21, sometimes 10, 11, 12 and 13.  So I went into the Attributes and Abilities tab from the top of the Character Sheet.  I set the "ac" box to be 16, as I believe that is supposed to be the base ac amount.  Then I went to the Character Sheet, it showed 16.  So I clicked on the Shield which added 2, and then clicked on defense which added 1.  Then I clicked off Shield and the AC went to 10.  And it just went downhill from there. What am I doing wrong here???

Hi Colby, The Dungeon Mann,  It definitely sounds weird. Without coming and taking a look I could only play guessing games. Mind sending me an invite so I can come take a look?

AC is a calculated attribute, changing the value under the attributes and abilities tab will only temporarily change it until something causes it to be recalculated.  Under inventory items check the armor, click on the little dot by the weight - it should display the details of the armor and under Mods it should say something like AC: 16.  If it doesn't delete it, then drag and drop a new set of armor from the compendium.  Next check the shield, it should say AC: +2 or AC: 2, if not delete and re-add from compendium.  Finally look under Global AC Modifiers and make sure Defense Fighting is there and set to 1.  Other things that might modify AC;  some races have natural armor higher than AC 10, a multi-class in barbarian or monk can affect unarmored AC, dexterity bonus if not wearing heavy armor, some magic items, or any other Global AC Modifiers that are enabled. One more thing:  Under the sheet settings, make sure custom AC is set to NONE and Allow Shields is checked.

Okay solved now, thank you!! There wasn't any text in the "mod" field when I clicked the inspect from the inventory.  Looks like the player deleted his previous Chain Mail when he found the Mithral version in the Dragon of Icespire Peak campaign and just typed in the name of it and clicked equipped, and also did that when he bought a new shield in town. So I deleted those, dragged the Chain Mail and Shield from Compendium, and just renamed it to "Mitral Chain Mail" for the player and now it seems to be calculating okay.   Thanks so much!!!