Is it permissible to send blessings upon the Prophet (peace and blessings be upon him) when his name is mentioned during the prayer?
Machine translationRead the Arabic original
Question : This is 'Amr ibn 'Umar. Is it permissible to send blessings upon the Prophet (peace and blessings be upon him) when his name is mentioned during the prayer? And is it permissible for the one praying to glorify Allah when the imam recites [Al-A'la 87:1]?
Answer : There is nothing wrong with that.
Exalt the name of your Lord, the Most High,
سَبِّحِ اسْمَ رَبِّكَ الْأَعْلَىAnswer : There is nothing wrong with that.
Source
قناة «فضيلة الشيخ محمد بن صالح العثيمين»، 2946 - هل يجوز أن نصلي على النبي ﷺ إذا ورد ذكره في الصلاة؟ ابن عثيمين — youtube.com
The Arabic text is a machine transcription of the audio recording.