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Office365.SendEmail' has an invalid value for parameter 'To

I receive this message "Office365.SendEmail' has an invalid value for parameter 'To" because I am using at OnSelect;


Office365.SendEmail(Gallery1.Selected.'E-Mail',"Thank you for visiting" , "You have been de-registered")


But not everyone fills in the e-mail field: Gallery1.Selected.'E-Mail' which causes the error.


How can I prevent the error without making the field a mandatory field?

Community Support
Community Support

Hi @SdR1,


An error message would be returned whenever a required parameter is blank in the function.

Please take a try with the following code which will send out the email without issues:

Add a button under the gallery and set its OnSelect property:




Best regards,



Community Support Team _ Mabel Mao
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

Hi @v-yamao-msft


Did what you suggested and now have in the OnSelect of the Button;


If(IsBlank(Gallery1.Selected.'E-Mail'),"",Office365.SendEmail(Gallery1.Selected.'E-Mail',"Thank you for visiting" , "You have been de-registered"))


But I still receive the same error message.

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