Unable to Book Turkish Airlines Strasbourg to Istanbul Flights Online

I live in Offenburg, Germany, and I usually fly from Strasbourg to Istanbul with Turkish Airlines. For about a month now, I've been unable to purchase tickets online for this route. The flights appear to be closed, and I can't view any available options from Strasbourg to Istanbul. All other flights are open and visible to me, but not this one. This is incredibly frustrating since I rely on this route regularly. I've tried multiple times and even used different devices, but the issue persists. Turkish Airlines, please fix this problem immediately and allow me to book tickets online for the Strasbourg/Istanbul route. I urgently need to make travel arrangements, and your prompt attention to this matter would be greatly appreciated.