Very common with old liquid adex that has sat for over 5 months. (please note in the time since chem companies including us have updated to much more stable solution) But since your product is over half a year old:
Your easiest solution would be to get a new bottle, but there are also methods to dilute the solution or convert your solution into vodka based. Heating will only lead to bigger crystals later. Your solution is now lower in available adex, as over time the solution has become supersaturated.