I used to come to the Prophet ﷺ and ask permission to enter. If he was in prayer, he would say "Subhan Allah," and if he was not in prayer, he would grant me permission.
حدثنا عبد الله حدثني أبو كريب محمد بن العلاء حدثنا ابن المبارك عن يحيى بن أيوب عن عبيد الله بن زحر عن علي بن يزيد عن القاسم عن أبي أمامة قال
كنت آتي النبي ﷺ فأستأذن فإن كان في صلاة سبح وإن كان في غير صلاة أذن لي
Its isnad is extremely daif. Yahya bin Ayub is Alghafiqi Almisri, and he is trustworthy.Ubaydullah bin Zahr, with the zay having a fatha and the ha with sukun, is truthful but makes mistakes. Some have deemed him trustworthy while others have deemed him daif. Bukhari said, his hadith is close to acceptable. But the real problem lies with Ali bin Yazid.Ali bin Yazid is Alalhani, with the hamza having a fatha and the lam with sukun, and he is extremely daif. Bukhari said, his hadith is denounced and he is daif.Qasim is Ibn Abdul-Rahman Alshami, Abu Abdul-Rahman. There has been disagreement about him, but the truth is that he is trustworthy, and the weakness found in some of his hadiths comes from those who transmitted from him.In Tahzib 7:13, in the biography of Ubaydullah bin Zahr, Ibn Hibban said, he transmits fabrications from reliable narrators. So when he transmits from Ali bin Yazid, he brings forth calamities. And when a report's isnad combines Ubaydullah bin Zahr, Ali bin Yazid, and Qasim Abu Abdul-Rahman, the content of that report is nothing but what their own hands have fabricated. End of quote.Among these three, none has been accused of fabrication except Ali bin Yazid. As for the other two, they are basically truthful, even though they make mistakes.This hadith is among the additions of Abdullah bin Ahmad. As for its content, its meaning has already been given earlier with another isnad, 570.