I am taking 40mg lisinopril twice a day is it ok?

Yes, you are at the maximum recommended dose level. Keep at eye out for side effects such as cough;dizziness, drowsiness, headache or depressed mood.

https://www.drugs.com/lisinopril.html

The recommended starting dosage of lisinopril for people with high blood pressure (hypertension) is 10 mg, taken once daily. Based on the blood pressure response and/or side effects of lisinopril, the dosage may be increased or decreased.

For most people, the normal daily dose is 20 mg to 40 mg. For each change in your lisinopril dosage, it may take several weeks to see the full effects on blood pressure.

If your doc has prescribed the dosage it should be ok after having assessed your high BP.

Take care, best wishes!