All of my PCs are having trouble casting spells

When they click on a spell to cast it, it just doesn't show up. I went into their character sheets to see if I could troubleshoot and am experiencing the same issues. Anyone else had this problem or know a fix for it?

Which sheet, and how were the spells added? (Compendium drop, manually entered?)

First question:  What character sheet are you using?  There's quite a few out there ;) Assuming you're using the 5e OGL character sheet, first thing to try is to edit the spell, change the output from attack to spellcard and back or vice versa and that should fix things up. If that desn't work, would you please carefully work through the first three steps of our guide to Solving Technical Issues ? Step 1: Make sure to use the right browser Please check if these issues persist when using both Chrome and Firefox. Step 2: Ensure that there are no extensions/addons interfering with Roll20 Please disable all add-ons/extensions and anti-virus programs. Step 3: Clear your cache If none of the above succeeds, please thoroughly work through Step 4 . (Don't forget the complete Console Log!) If you ARE NOT using the 5e OGL Character sheet, advice will have to wait until you tel us your sheet :)