Mystryl is currently not being recognised as a valid deity for clerics or just as a choice for any PC.
The specific message is:
[Deities] You do not have a valid deity for this setting. (Mystryl)
[Divine Spellcasting] - You cannot cast divine spells without a valid deity.
- Your cleric's alignment is not favored by your deity, and you cannot cast spells.
- Your cleric's domains are not supported by your deity, and you cannot cast spells.
PC Alignment was TN with Illusion and Magic domains which should be legal as per the restrictions presented (//%22http://www.escapefromundeath.com/forums/showthread.php?t=9465%22).
Fixed next reset.