I'm sorry for your loss.
Since your husband died in 2017, you can still file married filing jointly on your 2017 return.
However, your return was probably rejected because the Social Security Administration has frozen your husband's social security number. [They do this to prevent fraud and identity theft.]
You will have to print your return and mail it in. You will sign as "Surviving Spouse," which notation will appear on the Form 1040.
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